- Email: [email protected]
The influence of film-induced mood on pain perception
Pain 76 (1998) 365–375
The influence of film-induced mood on pain perception Matisyohu Weisenberg*, Tal Raz, Tamar Hener Department of Psychology, Bar-Ilan University, Ramat-Gan, Israel Received 5 August 1997; received in revised form 17 March 1998; accepted 27 March 1998
Abstract It has been shown that a person’s mood can influence pain tolerance. Films have been used as a means of inducing a desired mood. The effect on pain perception of film type and film length to induce mood was investigated. Previous research with brief humorous films had not indicated any unique advantage of humor over distraction approaches. Other recent research had indicated that after exposure to film stimulation there is a need to wait approximately 40 min before physiological changes can be obtained. Thus, the present study varied both film type and length and introduced a 30-min waiting period following the mood induction via film prior to exposure to cold-pressor pain. Two hundred subjects in nine different groups participated in the study. Three types of films were used: (1) humorous, (2) holocaust, (3) neutral. Three lengths of each type were also used: 15 min, 30 min, and 45 min. In addition, a tenth no-film group served as a control for the effects of a film. Each subject was given a baseline trial of cold-pressor pain, a trial immediately following the film and a trial 30 min later. Results indicated an advantage in increased pain tolerance for the humorous film and an increased pain tolerance for the longer film regardless of type only after the 30-min waiting period. Results were discussed from a pain theoretical perspective with emphasis placed on returning to psychological manipulations of the sensory aspects of pain and not just the cognitive/emotional/motivational dimensions. 1998 International Association for the Study of Pain. Published by Elsevier Science B.V. Keywords: Humor; Mood; Sensory effects; Cognitive effects
1. Introduction The purpose of the present study was to assess the effects on pain perception of film-induced mood as a function of film type and film length. The long-term goal is to develop techniques that are scientifically and theoretically sound and applicable to the clinical setting. Mood, and especially depression, has been shown to have an influence on pain perception and pain tolerance. The association of pain and depression has a long history in the pain control literature. Sternbach (1974) reviewed studies that indicated that pain may occur in place of depression and that use of antidepressant medication can alleviate the pain. Blumer and colleagues (Blumer and Heilbronn, 1982; Blumer et al., 1982) presented evidence that chronic psychogenic pain patients appear to suffer from depression. The evidence included psychodynamic factors as well as biological markers. These patients responded well to anti-
* Corresponding author. Tel.: +972 3 5318539; fax: +972 3 5350267.
depressant medication. However, even in 1982, the connection of pain and depression was not received without criticism. Merskey (1982) and Pilowsky (1982), although acknowledging that pain and depression do occur jointly, felt that it would be a mistake to view chronic pain only from the perspective of depression. The literature on pain and depression is vast. In a Medline search from 1983 to 1997, 3232 citations were noted. Indepth review of this entire literature is beyond the scope of this introduction. More recent reviews of the literature indicate that depression could lead to pain, pain could lead to depression, and it is possible that both pain and depression use the same mechanisms, especially the serotonin pathways (Pilowsky, 1988; Gamsa and Vikis-Freibergs, 1991; Craig, 1994). The positive effects of antidepressant medications such as amitriptyline have been attributed to the elevation of the depressive mood of the patient (Bryson and Wilde, 1996). However, Harrison et al. (1997) indicated that three months of treatment with antidepressant medication reduced pain severity and distress in nondepressed patients. This latter finding is consistent with the idea that
0304-3959/98/$19.00 1998 International Association for the Study of Pain. Published by Elsevier Science B.V. PII S0304-3959 (98 )0 0069-4
366
M. Weisenberg et al. / Pain 76 (1998) 365–375
the effectiveness of antidepressant medication in the treatment of chronic pain may not be due to the reduction of depression. Despite the findings that pain and depression are not always directly linked, there are enough findings to indicate a meaningful relationship of pain and depression. For example, Krittayaphong et al. (1996) reported that depressed compared to nondepressed heart patients complained more of anginal pain. In chronic low back pain depression is also very prevalent (cf. Gallagher et al., 1995). Overall, negative mood has been found to be related to pain severity (Shacham et al., 1984). Mood states of tension, irritability, depression and tiredness have been found to increase two days before migraine headache attacks (Spierings et al., 1996). Mood disturbance scores and reports of pain in oncology patients were found to be related (Glover et al., 1995). Even in infancy, mother’s mood ratings of their children were found to predict how the infants would react following blood sampling (Bonichini and Benini, 1995). As reviewed earlier (Weisenberg et al., 1996b), the use of humor has a long history. It has been seen as a means to deal with frightening situations (Dixon, 1980; Thorson, 1985), anxiety reduction (Cohen, 1989), anger and depression reduction (Philip and Judd, 1982), and as a means of producing an overall atmosphere of relaxation and comfort for terminal patients (Urba, 1996). Humor is said to produce a variety of physiological effects from increased catecholamine and endorphin levels (Haig, 1988) to reduced muscle tension (Moody, 1978). In a recent study, Newman and Stone (1996) were able to demonstrate that the production of humor while being exposed to an aversive stimulus yielded lower negative affect, lower tension, and reduced psychophysiological reactivity. Interestingly, with all the qualities attributed to humor, there have been few controlled studies in the application of humor to pain reduction and tolerance. The previous research of Weisenberg et al. (1996b) was not able to demonstrate a unique advantage in the use of humor above and beyond that of distraction. Study participants were briefly exposed to filmed material during which they were asked to immerse their arms in water that was cooled to 1°C. They continued watching the films while receiving the stimulation. Recent work, that has demonstrated that filmed materials can influence the immune system, has argued that at least 40–45 min are required for the stimulus to produce the desired effects (Mittwoch-Jaffe et al., 1995). This work has suggested that the Weisenberg et al. (1996b) study of humor may not have been adequate from a time perspective in order to demonstrate some novel aspects of humor. On the basis of these previous studies it might be possible to conclude that shorter exposure times may lead to a distraction effect, while longer exposure times may show outcomes that are more uniquely related to humor. This report is an extension of our previous work on the use of humor and filmed materials as a means of
increasing pain tolerance (Weisenberg et al., 1996b). The length of the mood-induction stimuli was varied and a delayed test of their effects was introduced. Although the present study used films to induce mood, there have been many other techniques used. One of the most widely used approaches to induce a given mood, as seen in the experimental literature, is the Velten procedure (Velten, 1968). In this procedure subjects are given a number of statements to induce a specific mood such as euphoria or depression. Meta-analysis of many studies has indicated that the procedure is valid (Larsen and Sinnett, 1991). Zelman et al. (1991) used the Velten procedure to induce depressive, neutral or euphoric states. Subjects were given cold-pressor pain. Pain tolerance, but not pain ratings, was affected. Subjects in the euphoric group increased, while subjects in the depressive group decreased, tolerance time in comparison to the neutral group. By contrast, contrary to Zelman et al. (1991), Berntzen and Sen (1986) using the Velten procedure found that the depressive but not the positive mood induction led to an increase in cold-pressor tolerance while both conditions led to an increased pain rating. Aside from the issues of what subjects actually experience when the Velten induction is used, research has indicated that the effects of the Velten induction do not last more than a very short time, approximately 10 min, and the effects can be dissipated easily by intervening tasks (Frost and Green, 1982; Isen and Gorgolione, 1983). As the ultimate goal is application to a clinical setting, it was felt that the use of filmed materials to induce mood would be more appropriate. This decision was strengthened by the recent review of mood-induction procedures (GerrardsHesse et al., 1994) that rated films as the first method of choice for the induction of elation and depression. One of the goals of this study was to assess the effect of the film mood induction after 30 min of waiting. Would the effect of the mood induction, unlike the Velten procedure, be longerlasting and hence more applicable in a clinical setting? To summarize, the purpose of this study was to assess the effects on pain perception of film-induced mood as a function of film type and film length. A further goal of this study was to assess the effect of the mood induction after 30 min. The ultimate goal is to lead to techniques that could be used in a clinical setting.
2. Method 2.1. Subjects Two hundred volunteer, paid subjects (100 males and 100 females) aged 18–36 years (median = 23) recruited by posters participated in the laboratory study. The main inclusion or exclusion criterion was the subject’s health status as determined by the health questionnaire. All subjects were told that the cold-pressor stimulus could cause pain. They were told that they could quit at any time and were asked to
367
M. Weisenberg et al. / Pain 76 (1998) 365–375
sign informed consent agreements. One hundred and eighty subjects were shown a film while 20 subjects experienced the pain stimuli but did not view a film. An additional 29 subjects started the study but were discontinued, as they had reached the ceiling maximum of 4 min of cold-pressor stimulation in the first trial and could not show any additional increase in tolerance. Subjects were randomly assigned to the different groups. 2.2. Film stimuli Three types of films were chosen: (1) a humorous film to induce a positive mood, (2) a holocaust film to induce a negative mood, and (3) a neutral film on alligators. Each film type was shown for either 15, 30 or 45 min. The negative stimulus was taken from the study of Mittwoch-Jaffe et al. (1995) that demonstrated a physiological influence on parameters of the immune system as a result of watching the film. Each film was rated by 10 judges for a total of 90 different judges (see Table 1). Judges were recruited in a similar manner as the subjects and were of approximately the same age. Films were rated from 1–5 for the level of interest (1 = very interesting, 5 = very boring), for the level of mood (1 = very happy, 5 = very sad), and for the level of the subject’s mood as a consequence of viewing the film (1 = very happy, 5 = very sad). Two-way analysis of variance (3 types of film × 3 lengths of film) indicated that for interest, the films did not yield differences for type of film (F(2,81) = 1.33, P . 0.05), nor for length of film (F (2,81) = 0.41, P . 0.05), nor for the interaction of type of film by length (F(4,81) = 0.90, P . 0.05). Two-way analysis of mood ratings of the films yielded significance for type of film (F(2,81) = 502.75, P , 0.001). Multiple contrast analysis by the Scheffe method indicated that the humorous film was judged as happier than the neutral film that in turn differed from the holocaust film. The holocaust film, in turn, was judged as sadder than either the humorous or neutral film. Length of film was not significant (F(2,81) = 2.18, P . 0.05) nor was the interaction of type of film by length (F(4,81) = 1.80, P . 0.05). Analysis of variance of the induced mood of the judges indicated significant differences for the type of film (F(2,81) = 144.38, P , 0.001). Multiple contrast analysis by Scheffe indicated that the humorous
film yielded a happier mood than the other two films, while the holocaust film yielded a sadder mood than the other two films. No differences of induced mood were obtained for length of film (F(2,81) = 2.36, P . 0.05) nor for the interaction of type of film by length (F(4,81) = 0.53, P . 0.05). During the study itself, additional ratings of film mood and induced personal mood were obtained from participants (Table 2). Analysis of variance (3 types of films × 3 levels of length) indicated that the film mood ratings differed as a function of type of film (F (2,171) = 447.63, P , 0.001). Multiple contrast analysis by Scheffe indicated that the each film significantly differed from the other in the desired direction. Neither film length (F(2,171) = 0.45, P . 0.05) nor the interaction of film type by length (F(4,171) = 1.27, P . 0.05) were significant. The induced personal mood ratings were also subjected to analysis of variance (3 types of films × 3 levels of length). Results indicated that the induced personal mood ratings differed as a function of type of film (F(2,171) = 124.62, P , 0.001). Multiple contrast analysis by Scheffe indicated that each film significantly differed from the other in the desired direction. Neither film length (F(2,171)= 0.14,P . 0.05) nor the interaction of film type by length (F(4,171) = 0.90, P . 0.05) were significant. Following the second immersion, the groups still showed significant differences in the desired direction (F(2,171) = 30.73, P , 0.001). Multiple contrast analysis by Scheffe indicated that the types of films each differed from each other. Following the third immersion, the mood ratings did not differ from each other as a function of type of film. 2.3. Pain stimuli Cold-pressor was chosen as the pain stimulus as it has been used in many of the cognitive studies and there are readily available norms (Hilgard, 1969). The water was maintained at 1°C by an immersion cooler and kept in constant circulation by an underwater mixer. On instruction, the subject immersed his/her arm in the water by pressing down on the arm rest on which the subject kept his/ her left arm, simultaneously starting a clock to measure
Table 1 Mean ratings by judges of the mood and interest level of the films and the induced personal mood the films produced Type of film Humorous
Film interest Film mood Personal mood
Neutral
Holocaust
15 min
30 min
45 min
15 min
30 min
45 min
15 min
30 min
45 min
2.70 2.20 2.50
2.55 2.00 2.11
2.80 2.00 2.20
2.50 3.00 3.00
2.09 2.90 2.09
2.60 3.00 3.00
2.50 4.60 4.40
2.60 4.50 4.10
2.30 4.90 4.40
Interest: 1 = very interesting, 5 = very boring. Mood: 1 = very happy, 5 = very sad. For each cell n = 10.
368
M. Weisenberg et al. / Pain 76 (1998) 365–375
insertion time. The maximum time in the water was limited to 240 s. 2.4. Skin resistance Skin resistance response (SRR) is a commonly used measure of sympathetic arousal in pain studies (cf. Arntz and Lousberg, 1990; Al Absi and Rokke, 1991; Weisenberg et al., 1996a). SRR electrodes were placed on the index and middle finger of the right hand. SRR was measured via an Atlas Scanmaster 8600-3 computer physiograph. Samples of SRR in ohms (Q) were obtained prior to immersion and for the highest point reached every 10 s while the arm was in the water. 2.5. Verbal measures The State-Trait Anxiety Inventory (STAI), developed by Spielberger et al. (1970), is a 40-item measure of how anxious the subject felt at the moment and how anxious he/she feels generally. Two scores are derived: (1) State anxiety, and (2) Trait anxiety. Scores had a possible range from 20 to 80 for each of the anxiety scales. For this study the reliability for State anxiety was a = 0.87 and for Trait anxiety a = 0.85. The Humor Questionnaire developed by Ziv (1981) is a 14-item scale that measures appreciation of humorous situations and ability to cause others to laugh. Three scores can be derived: (1) General score which is the sum of responses to the entire scale, (2) Humor appreciation which is the sum of responses to the first seven items, and (3) Humor production which is the sum of the last seven items. Overall reliability of the scale as obtained in this study was a = 0.80. The perceived self-efficacy of pain control is a 14-item measure that refers to the judgment a person makes concerning his ability to execute certain actions to deal with his/ her environment (Bandura, 1982; Mittwoch et al., 1990). The score is the sum of the responses to the entire scale. In this study it referred to the subject’s perceived ability to control pain associated with cold water. The scale was administered prior to the cold-pressor stimulation and as part of the post-experimental questionnaire. The scale reliability for this study was a = 0.92.
Pain and anxiety ratings were obtained immediately following the removal of the subject’s arm from the water. Subjects were asked to rate the pain and present feelings of anxiety on visual analog scales as used in earlier studies (Weisenberg et al., 1985; Mittwoch et al., 1990). It is possible to obtain pain ratings during the stimulation itself. This was not done so that the act of measurement in and of itself should not interfere with the experimental results as can occur (Weisz, 1997). In addition, the outcome of the study was based on a number of additional measures such as duration in water, skin resistance, etc. Mood ratings were obtained following the subject’s viewing of the films and following the subject’s immersion in the water. Two measures were used: (1) a visual analog scale of mood in which ratings of 1 = very happy and 5 = very sad; and (2) the scale to measure depressive mood (Zuckerman and Lubin, 1965). This scale consisted of 34 adjectives in which 22 words described depressive feelings while 12 described satisfied feelings. The depressive items and the non-endorsed satisfied items are added together to yield a total score. Reliability for this study was a = 0.78. The post-experimental questionnaire was designed to measure the subject’s ratings of task importance, perceived success in coping and ratings of the helpfulness of the films. 2.6. Procedure After obtaining an informed consent agreement and after health screening, each subject was asked to complete the STAI, the Humor Questionnaire, and the self-efficacy questionnaire. Subjects were told that we were interested in studying the relationship between a person’s mental status and his physiological reactions. As part of the study he/she would be asked to respond to a number of questionnaires, have electrodes attached, be shown a film (for the film conditions), be asked to immerse an arm in cold water that some people feel is painful but not dangerous. The subject was then seated in an electrically isolated booth where electrodes were attached. Five minutes of relaxation were given to permit the subject to adjust to his/her surroundings and to permit the experimenter to calibrate the polygraph. The subject listened to pre-recorded instructions. At the
Table 2 Mean subject ratings of film mood and induced personal mood obtained during the study Time of rating
Type of film Humorous
Following film Following film After immersion 2 After 30-min wait
Film mood Personal mood Personal mood Personal mood
Neutral
Holocaust
15 min
30 min
45 min
15 min
30 min
45 min
15 min
30 min
45 min
2.25 2.40 2.60 2.85
2.05 2.25 2.40 2.65
2.20 2.20 2.50 2.95
2.90 2.75 2.55 2.60
2.95 3.00 2.65 2.75
2.65 2.80 2.80 2.85
4.85 3.90 3.15 2.80
4.80 3.90 3.30 3.05
4.90 4.00 3.40 2.95
Mood: 1 = very happy, 5 = very sad. For each cell n = 20.
M. Weisenberg et al. / Pain 76 (1998) 365–375
369
Fig. 1. Mean time (s) hand in water as a function of type of film. Analysis indicated that the immersion after 30 min yielded a significant difference between films. As can be seen, the humorous film showed a continuous increase in pain tolerance as compared to the others.
end of relaxation, the subject was asked to insert his/her arm into the water and to keep it there until (s)he felt (s)he could no longer do so. For all immersions the experimenter limited the time to 4 min without informing the subject. After the arm was removed from the water, subjects were asked to rate the pain, anxiety during immersion, and present mood. At this point, for the film conditions, a movie was shown appropriate to the group in which the subject belonged. This was followed by mood ratings. For the no-film group, in place of the film, subjects were asked to wait while the apparatus was being recalibrated. Following a 30-min wait, for the no-film group, mood ratings were obtained. No-film subjects were once more asked to insert his/her arms in the water. After removal of the arm from the water, another rating of pain, anxiety and mood was obtained. Following the second immersion, film-group subjects were asked to wait while recalibration took place. This was for 30 min. To assess the effect of the boredom of waiting, half of the subjects were kept occupied by being asked to read neutral material. No differences were obtained for the two waiting groups and hence all results used the combined waiting data. Mood ratings were obtained at the end of the waiting period. A third immersion followed the waiting period. Once more ratings of pain, mood and anxiety were obtained. The post-experimental questionnaire and subject debriefing took place outside the experimental booth.
from each other prior to the experimental manipulation. Therefore, subjects in the different groups should not have differed on measures of mood nor on the reactions to the initial cold-pressor experience. To reduce influences of differences on these initial starting point, analysis of covariance was used. To eliminate the effects of differences in mood with which subjects may have come to the study, the Zuckerman and Lubin (1965) depressive mood ratings were held constant for each immersion. For the second and third cold-pressor experiences, duration of the first immersion also was added as a covariate as this starting point should not have been different between groups. The basic statistical analysis was a 3 (type of film) × 3 (film length) × 2 analysis of covariance (ANCOVA) 3.1. Duration
3. Results
For the groups that viewed a film, inspection of the duration data indicated that there were instances in which the standard deviations were larger than the means. To reduce the possible effects of this problem, a logarithmic transformation of the data was used in all analyses of the duration scores.1 For the first and second immersions, no significant differences were obtained. For the third immersion, with the first immersion as a covariate, a significant difference was obtained for the type of film (F(2,169) = 3.60, P = 0.02). Analysis by the Scheffe indicated that the humorous film yielded a higher duration in water as compared with the other two that did not differ from each other (Fig. 1). In addition, a significant result was also obtained for film length (F(2,169) = 2.90, P = 0.05) (Fig. 2). Analysis by
The analyses of the data were based on the assumption that the subjects in the different conditions did not differ
1 Although analysis of the data without transformation yielded even more powerful effects, it was felt that this would be problematic in terms of the statistical assumptions.
370
M. Weisenberg et al. / Pain 76 (1998) 365–375
Fig. 2. Mean time (s) hand in cold water as a function of viewing time. Analysis indicated that the 45-min longer viewing time yielded significantly higher pain tolerance.
the Scheffe indicated that immersion time was longer for the 45-min film than for either the 30- or 15-min films that did not differ from each other. None of the interactions reached a level of significance. For all of the analyses, no differences were obtained as a function of sex. To assess the effect of viewing a film, the nine film groups were collapsed into three according to type of film. They were compared with the no-film control group in a one way ANCOVA with the Zuckerman and Lubin ratings held constant for the first immersion. For the second and third immersions, the first immersion duration also was added as a covariate. No differences were obtained for the first or second immersions. For the third immersion, a significant
difference was obtained (F(3,194) = 3.38, P = 0.01). Scheffe analysis indicated that the no-film control group yielded the lowest duration in the water. 3.2. Pain ratings For the groups that viewed a film (see Table 3), no significant differences were obtained for the first and second immersions. For the third immersion, with the Zuckerman and Lubin ratings and the first immersion as covariates, no significant difference was obtained. When the Zuckerman and Lubin ratings and the second immersion pain ratings were used as covariates, a significant difference was obtained for the type of film (F(2,170) = 3.34, P = 0.03).
Table 3 Mean pain ratings and standard deviation following arm immersion in water by length and type of film Immersion trial 1
2
3
Length of film (min) 15 30 45 Total 15 30 45 Total 15 30 45 Total
Type of film
Total
Holocaust
Neutral
Humorous
69.62 66.82 67.25 67.90 67.25 63.75 61.90 64.30 64.30 68.50 61.75 64.85
60.82 64.17 61.18 62.06 52.00 57.25 60.50 56.55 51.75 58.15 60.75 56.88
69.62 62.75 72.19 68.18 67.45 55.50 71.00 64.65 61.70 52.15 62.75 58.86
(19.70) (15.91) (16.26) (17.12) (17.28) (18.69) (16.49) (17.36) (19.62) (20.26) (19.28) (19.59)
(20.53) (15.35) (22.69) (19.48) (22.84) (20.34) (24.16) (22.40) (22.25) (22.00) (22.90) (22.33)
Scores ranged from 0 = no pain to 100 = extreme pain. For each cell n = 20.
(18.39) (15.25) (16.42) (16.91) (17.86) (20.89) (13.82) (18.90) (19.36) (19.85) (17.65) (19.26)
No film
66.69 (19.68) 64.58 (15.32) 66.87 (18.93) 69.48 (18.41) 62.23 (20.50) 60.12 (19.78) 64.46 (18.95) 64.21 (19.09) 59.25 (20.83) 59.60 (21.48) 61.75 (19.74) 73.25 (16.40)
371
M. Weisenberg et al. / Pain 76 (1998) 365–375
Scheffe analysis indicated that the humorous film showed a reduced pain rating from immersion 2 to immersion 3 as compared with the other two film groups that did not change. No significant differences were obtained for sex, film length nor for any of the interactions. To assess the effect of viewing a film, the nine film groups were collapsed into three according to type of film. They were compared with the no-film control group in a one-way ANCOVA with the Zuckerman and Lubin ratings held constant for the first immersion. For the second and third immersions, the first immersion pain rating also was added as a covariate. No differences were obtained for the first or second immersions. For the third immersion, a significant difference was obtained (F(3,194) = 3.72, P = 0.01). Scheffe analysis indicated that the no-film group showed the highest pain rating compared to the other film groups that did not differ from each other. 3.3. SRR For the groups that viewed a film, ANCOVA was conducted for SRR measures obtained for the highest level reached in the first 10 s for each immersion with the Zuckerman and Lubin (1965) depressive mood ratings held constant for the first immersion (see Table 4). For the first immersion, no significant differences were obtained for type of film nor for film length. A sex difference was obtained (F(1,150) = 5.28, P = 0.02). Women yielded a higher level of SRR than men (M = 3291.8, M = 2463.6, for women and men, respectively). For the second immersion in addition to the Zuckerman and Lubin ratings, the SRR of the first immersion was also added as a covariate. Significant differences were obtained for film length (F(2,152) = 3.03, P = 0.05). Scheffe analysis indicated that the 45-min film yielded the lowest level of SRR. No differences were obtained for the type of film nor for the interactions. Here, too, a significant sex difference was obtained (F(1,143) = 3.62, P = 0.05). Women yielded a
higher level of SRR than men (M = 2353.6, M = 1986.5, for women and men, respectively). For the third immersion, with the Zuckerman and Lubin ratings and the first immersion SRR as covariates, no significant difference was obtained. When the Zuckerman and Lubin ratings and the second immersion SRR were used as covariates a significant difference was obtained for the type of film (F(2,157) = 3.47, P = 0.03). Scheffe analysis indicated that the neutral film showed the lowest SRR as compared with the other two film groups. No significant differences were obtained for sex, film length nor for any of the interactions. To assess the effect of viewing a film, the nine film groups were collapsed into three according to type of film. They were compared with the no-film control group in a one way ANCOVA with the Zuckerman and Lubin ratings held constant for the first immersion. For the second and third immersions, the first immersion SRR also was added as a covariate. No differences were obtained for the first, second or third immersions. 3.4. Anxiety ratings For the groups that viewed a film, no significant differences were obtained for the first and second immersions. For the third immersion, with the Zuckerman and Lubin ratings and the first immersion anxiety ratings as covariates, no significant main effects were obtained. However, a significant interaction of type of film and film length was obtained (F(4,169) = 3.15, P = 0.01). Further analysis by the Duncan test indicated that the anxiety ratings for the neutral film were lowest for the 15-min length compared to the 30and 45-min films (M = 6.58, M = 20.85, M = 18.99, for the 15-, 30- and 45-min films, respectively). For the humorous (M = 9.92, M = 18.99, M = 21.91, for the 15-, 30- and 45-min films, respectively) and for the holocaust films (M = 17.71, M = 13.30, M = 18.10, for the 15-, 30- and 45-min films, respectively), no differences were obtained.
Table 4 Mean SRR (Q) and standard deviation during arm immersion in water by length and type of film Immersion trial 1
2
3
Length of film (min) 15 30 45 Total 15 30 45 Total 15 30 45 Total
For each cell n = 20.
Type of film
Total
Holocaust
Neutral
Humorous
3066 3786 2786 3213 2246 2635 1657 2208 2680 2823 2472 2156
3279 2440 2869 2863 2902 2162 1882 2302 1915 1824 2256 1997
2285 1960 3229 2491 2162 1842 2020 2002 2372 2030 2078 2665
(2370) (3375) (2544) (2768) (1372) (1937) (997) (1534) (2174) (2295) (2561) (1619)
(2817) (2417) (2464) (2536) (2512) (1602) (1316) (1878) (1154) (1536) (1314) (1340)
(1333) (1063) (2311) (1734) (2126) (1597) (947) (1585) (1964) (1741) (1116) (2303)
No film
2876 (2240) 2729 (2534) 2961 (2399) 2810 (1817) 2433 (2036) 2206 (1717) 1866 (1091) 2208 (2267) 2323 (1814) 2215 (1893) 2258 (1712) 2007 (1723)
372
M. Weisenberg et al. / Pain 76 (1998) 365–375
To assess the effect of viewing a film, the nine film groups were collapsed into three according to type of film. They were compared with the no-film control group in a one way ANCOVA with the Zuckerman and Lubin ratings held constant for the first immersion. For the second and third immersions, the first immersion anxiety ratings were also added as covariates. No significant differences were obtained. 3.5. Perceived self-efficacy Scores on the first measure of self-efficacy were divided at the median to permit an assessment for high and low selfefficacy. Data for each of the dependent variables of duration in water, pain ratings, SRR, and anxiety ratings were subjected to a 2 (high, low self-efficacy) × 3 (type of film) × 3 (length of film) ANCOVA with the Zuckerman and Lubin scale as a covariate on the first immersion and the results of the first immersion as an additional covariate for the second and third immersions. For the duration in water, no significant main effects or interactions were obtained. However, the overall correlation of self-efficacy and duration in water, although low, was significant (r = 0.20, P , 0.05). For pain ratings a significant difference for self-efficacy was obtained for the third immersion (F(1,160) = 6.49, P = 0.01). The high self-efficacy group yielded lower pain ratings (M = 56.46) than the low self-efficacy group (M = 63.51). For SRR a significant difference was obtained for the second immersion (F(1,143) = 5.19, P = 0.02). The high self-efficacy subjects yielded a lower SRR (M = 1887.2) compared to the low self-efficacy group (M = 2337.0). For anxiety ratings, a significant difference was obtained on the first immersion for self-efficacy (F(1,161) = 6.75, P = 0.01). High self-efficacy subjects rated themselves as less anxious (M = 18.10) than their low counterparts (M = 27.47). Overall, a significant low inverse correlation was obtained between self-efficacy and anxiety ratings (r = − 0.19, P , 0.05). The measure of self-efficacy in the post-experimental questionnaire was analyzed in a similar manner as the first self-efficacy measure with the first measure used as a covariate. No significant differences were obtained for type or length of film. 3.6. Humor Scores on the humor measures were divided at the median to produce high- and low-humor groups. Data for each of the dependent variables of duration in water, pain ratings, SRR, and anxiety ratings were subjected to a 2 (high, low self-efficacy) × 3 (type of film) × 3 (length of film) ANCOVA with the Zuckerman and Lubin scale as a covariate on the first immersion and the results of the first immersion as an additional covariate for the second and third immersions.
No significant differences were obtained for the different measures of humor (general, humor appreciation, humor production). 3.7. State-Trait Anxiety Scores on the State-Trait Anxiety Inventory were divided at the median separately for state and trait to permit an assessment for high and low anxiety. Data for each of the dependent variables of duration in water, pain ratings, SRR, and anxiety ratings were subjected to a 2 (high, low selfefficacy) × 3 (type of film) × 3 (length of film) ANCOVA with the Zuckerman and Lubin scale as a covariate on the first immersion, and the results of the first immersion as an additional covariate for the second and third immersions. The only significant difference for state anxiety was obtained for the rating of anxiety following the first immersion (F(1,161) = 22.85, P , 0.00). Lower anxiety ratings were obtained for the low state anxiety subjects (M = 14.39) compared to the high state anxiety subjects (M = 32.83). For trait anxiety, a significant result was obtained for the second immersion anxiety ratings (F(1,160) = 4.50, P = 0.03). Low trait anxiety subjects yieled lower anxiety ratings. (M = 14.82) compared to high trait anxiety subjects (M = 19.99). 3.8. Post-experimental questionnaire The variables of the post-experimental questionnaire, perceived task importance, perceived success in coping and perceived helpfulness of the films were subjected to a 3 (type of film) × 3 (length of film) ANOVA. No significant difference was obtained for perceived task importance or perceived success in coping. For perceived helpfulness, a significant result was obtained for type of film F(2,126) = 3.76, P = 0.02). Duncan analysis indicated that the neutral film was judged as less helpful (M = 1.33) than the humorous (M = 2.10) or the holocaust film (M = 2.37).
4. Discussion The purpose of this study was to assess the effects on pain perception for film-induced mood as a function of film type and film length. Results indicated a significant advantage for the humorous film that was obtained only after the 30-min waiting period. This was reflected in the increased pain tolerance time and in the pain ratings. In addition, there appears to be an advantage to the length of the film, regardless of content as seen by the increased duration in the cold water and by the lower level of SRR. The no-film group, in turn, showed less tolerance and gave higher pain ratings than the film groups. Once more, these effects were not immediately apparent. They occurred only after the 30min wait. Perceived self-efficacy in pain control yielded
M. Weisenberg et al. / Pain 76 (1998) 365–375
more immediate effects on some measures, anxiety, SRR and pain ratings. The results of this study raise a number of theoretical and practical issues. First is the question as to how to explain that the effects of the induction are obtained only after 30 min of waiting. One possible straightforward explanation can be based on memory and the fading of the memory trace over time. That is, the experimental session itself could have produced an emotional arousal (Weisenberg et al., 1996b). Over time some conditions were more effective and faded less easily than others. It is accepted that emotional memories fade less rapidly than non-emotional memories (Neisser, 1982). The humorous film and the longer films, therefore, may have faded less rapidly in comparison to the other conditions. From another perspective, pain has been viewed as consisting of a sensory component, a cognitive-emotional-motivational component and a central component (cf. Weisenberg, 1977; Melzack, 1986). Most of the psychological approaches have forsaken the sensory aspects of pain and are associated with changes in the cognitive-emotionalmotivational component of pain. The cognitive interventions mainly influence the person by affecting the way the pain is perceived, interpreted or related to rather than affecting the sensory component per se (Weisenberg, 1994). In turn, it is possible to place greater emphasis on the sensory component of pain. Using magnitude estimation procedures, Rollman and Harris (1987) reported on a series of obtained power functions ranging from 1.0 to 3.0. In a recent review, Rollman (1992) has analyzed some of these issues and attempts at separating the sensory and cognitive-emotional-motivational components of pain. Price et al. (1980) attempted to separate the sensory and the affective magnitudes of pain. They were able to do so only up to a point. Scales have been developed to distinguish between the different components of pain and have been used to assess the effects of interventions for pain control (e.g. Gracely et al., 1978). Another recent approach as represented by the functional theory of pain (Algom, 1992) places emphasis on the sensory component of pain. Using the methodology of psychophysics the theory attempts to determine how the sensory aspects of pain are perceived. There is an emphasis on the integration of stimuli from all the different sources that impinge on the individual before the final judgment of painfulness is made. This would also include mental attitude or prior preparation. According to the functional theory, pain perception can be reduced simply because the stimulus is processed by mechanisms unrelated to nociception. Pain perception can be influenced by interacting with other central mechanisms that are of either a cognitive or sensory origin. The final integration of the judgment of pain, according to this theory, deals primarily with the sensory aspects of pain. Rollman (1992) argues that with all the work done to separate the different components of pain, it is a task that
373
is not completely successful. The components of pain appear to be related to one another even though it is possible to place a greater emphasis on one aspect or another. Clark et al. (1989), for example, reported that cancer patients found sensory descriptors to have more emotional qualities than healthy controls. It is possible to speculate and apply these different approaches to the results of the present study as opposed to the earlier work (Weisenberg et al., 1996b). The earlier work in which the film was shown briefly and in which the subject was asked to immerse in cold water during the film was mostly effective as a cognitive distractor, affecting mainly the cognitive/emotional/motivational aspects of pain. In the current study subjects were exposed to longer film presentations and a longer time interval prior to receiving the pain stimulation. During the longer 30-min interval there was time for changes of a physiological nature to occur as described by Mittwoch-Jaffe et al. (1995). Hence, it is possible that the change that occurred, thus influenced the sensory aspect of pain as well as the cognitive–emotional aspects. Interestingly, there is research on exerciseinduced mood that also reported a maximal effect following a 10-min intervention to occur after 30 min (Thayer, 1987). The approach taken here might also help explain why certain of the psychological measures that, a priori, would relate to pain perception were not found to be as closely related to outcome as in prior studies. Firstly, it is interesting to note that the major increase in pain tolerance, was not in accordance with the mood ratings. There is the suggestion of a process that was begun via a mood induction that likely continued even though the original source of the induction was not seen in the mood ratings. Different systems may be functioning at different rates. In the present study, the humor scale did not show any differences. This is consistent with the earlier report of Newman and Stone (1996) who found no differences for both high and low scorers on the humor scale. The measure of self-efficacy of pain control in previous research was found to be more strongly related to outcomes (Weisenberg et al., 1996a). Self-efficacy likely reflects a person’s motivation to perform whatever is being measured. When referring to pain, self-efficacy refers to a willingness to continue or to tolerate the stimulation rather than a skill deficit (Maddux, 1995). In light of the weaker self-efficacy– pain relationship found in this study, it is likely that the cognitive/emotional/motivational aspects of pain played less of a role as compared to the physiological effects on the sensory component of pain. The above analysis implies that the psychological interventions for pain may be classified as affecting mainly different aspects of pain. Up to this point in time, the major emphasis of the psychological approach has been on techniques that reduce anxiety and increase motivation to accept the pain stimulation. Thus, for example, the appropriate preparation of mothers prior to birth emphasizes anxiety reduction and other cognitive techniques. It has been
374
M. Weisenberg et al. / Pain 76 (1998) 365–375
reported to reduce perceived pain by as much as 30% (Melzack, 1984). If techniques could be added to influence more effectively the sensory component of pain, perhaps the 30% could be raised to 50% or higher. In addressing the sensory aspects more directly, the major exception has been the use of hypnosis according to those theorists who do not view it as yet another cognitive technique (cf. Price, 1996). Fernandez and Turk (1992) have argued that these separate dimensions of pain exist but are related. Be that as it may, in the spirit of psychoneuroimmunology (Ader et al., 1991), perhaps it is time to once more turn to a greater emphasis on psychological approaches that will have a greater effect on the sensory dimensions of pain.
Acknowledgements This research was supported by a grant from the Koret Foundation. Gratitude is expressed to Yossi Gadot for his technical assistance in the conduct of this study.
References Ader, R., Felton, D.L. and Cohen, N. (Eds.), Psychoneuroimmunology, 2nd edn., Academic Press, San Diego, CA, 1991. Al Absi, M. and Rokke, P.D., Can anxiety help us tolerate pain?, Pain, 46 (1991) 43–51. Algom, D., Psychophysical analysis of pain: a functional perspective. In: H.G. Geissler, S.W. Link and J.T. Townsend (Eds.), Cognition, Information Processing and Psychophysics: Basic Issues, Erlbaum, Hillsdale, NJ, 1992, pp. 267–291. Arntz, A. and Lousberg, R., The effects of underestimated pain and their relationship to habituation, Behav. Res. Ther., 28 (1990) 15–28. Bandura, A., Self-efficacy mechanism in human agency, Am. Psychol., 37 (1982) 122–147. Berntzen, D. and Sen, B., Effects of experimentally induced positive and negative mood on laboratory pain. In: D. Berntzen. (Ed.), Analysis and Management of Experimental and Clinical Pain, University of Trondheim, Trondheim, Norway, 1986, paper IV, pp. 1–15. Blumer, D. and Heilbronn, M., Chronic pain as a variant of depressive disease, J. Nerv. Ment. Dis., 170 (1982) 381–406. Blumer, D., Zorick, F., Heilbronn, M. and Roth, T., Biological markers for depression in chronic pain, J. Nerv. Ment. Dis., 170 (1982) 425– 428. Bonichini, A. and Benini, F., Pain in infancy: individual differences, Percept. Motor Skills, 18 (1995) 142. Bryson, H.M. and Wilde, M.I., Amitriptyline. A review of its pharmacological properties and therapeutic use in chronic pain states, Drugs Aging, 8 (1996) 459–476. Clark, W.C., Ferrer-Brechner, T., Janal, M.N., Carroll, J.D. and Yang, C., The dimensions of pain: A multidimensional scaling comparison of cancer patients and healthy volunteers, Pain, 37 (1989) 23–32. Cohen, M.M., The Influence of Active Humor on the Level of Examination Performance, M.A. thesis, Tel-Aviv University, Tel-Aviv, Israel, 1989, 188 pp. Craig, K.D., Emotional aspects of pain. In: P.D. Wall and R. Melzack (Eds.), Textbook of Pain, 3rd edn., Churchill Livingstone, Edinburgh, 1994, pp. 261–274. Dixon, N.F., Humor: A cognitive alternative to stress? In: I.G. Sarason and C.D. Spielberger (Eds.), Stress and Anxiety, Vol. 7, Hemisphere Corp., Washington, DC, 1980, pp. 282–289.
Fernandez, E. and Turk, D.C., Sensory and affective components of pain: separation and synthesis, Psychol. Bull., 112 (1992) 205–217. Frost, R.O. and Green, M.L., Velten mood induction procedure effects: Duration and postexperimental removal, Pers. Soc. Psychol. Bull., 8 (1982) 341–347. Gallagher, R.M., Moore, P. and Chenoff, I., The reliability of depression diagnosis in chronic low back pain. A pilot study, Gen. Hosp. Psychiatry, 71 (1995) 399–413. Gamsa, A. and Vikis-Freibergs, V., Psychological events are both risk factors in, and consequences of, chronic pain, Pain, 44 (1991) 271– 277. Gerrards-Hesse, A., Spies, K. and Hesse, F.W., Experimental inductions of emotional states and their effectiveness: A review, Br. J. Psychol., 85 (1994) 55–78. Glover, J., Dibble, S.L., Dodd, M.J. and Miaskowski, C., Mood states of oncology outpatients: Does pain make a difference?, J. Pain Symptom Managem., 10 (1995) 120–128. Gracely, R.H., McGrath, P. and Dubner, R., Validity and sensitivity of ratio scales of sensory and affective verbal pain descriptors: Manipulation of affect by diazepam, Pain, 5 (1978) 19–30. Haig, R.A., The Anatomy of Humor: Biopsychosocial and Therapeutic Perspectives, C.C. Thomas, Springfield, IL, 1988,. Harrison, S.D., Glover, L., Feinmann, C., Pearce, S.A. and Harris, M., A comparison of antidepressant medication alone and in conjunction with cognitive behavioral therapy for chronic idiopathic facial pain. In: T.S. Jensen, J.A. Turner and Z. Wiesenfeld-Hallin (Eds.), Proceedings of the 8th World Congress on Pain, International Association for the Study of Pain, Seattle, WA, 1997, pp. 663–672. Hilgard, E.R., Pain as a puzzle for psychology and physiology, Am. Psychol., 24 (1969) 103–113. Isen, A.M. and Gorgolione, J.M., Some specific effects of four affectinduction procedures, Pers. Soc. Psychol. Bull., 9 (1983) 136–143. Krittayaphong, R., Light, K.C., Golden, R.N., Finkel, J.B. and Sheps, D.S., Relationship among depression scores, beta endorphin, and angina pectoris during exercise in patients with coronary artery disease, Clin. J. Pain, 12 (1996) 126–133. Larsen, R.J. and Sinnett, L.M., Meta-analysis of experimental manipulations: Some factors affecting the Velten mood induction procedure, Pers. Soc. Psychol. Bull., 17 (1991) 323–334. Maddux, J.E., Self-efficacy theory: An introduction. In: J.E. Maddux (Ed.), Self-efficacy, Adaptation and Adjustment: Theory, Research and Application, Plenum Press, New York, 1995, pp. 3–33. Melzack, R., Neurophysiological foundations of pain. In: R.A. Sternbach (Ed.), The Psychology of Pain, 2nd edn., Raven Press, New York, 1986, pp. 1–24. Melzack, R., The myth of painless childbirth, Pain, 19 (1984) 321– 337. Merskey, H., Comments on ‘Chronic pain as a variant of depressive disease: The pain-prone disorder’, J. Nerv. Ment. Dis., 170 (1982) 409– 411. Mittwoch, T., Weisenberg, M. and Mikulincer, M., The influence of warning signal timing and cognitive preparation on the aversiveness of electric shock, Pain, 42 (1990) 373–381. Mittwoch-Jaffe, T., Shalit, F., Srendi, B. and Yehuda, S., Modification of cytokine secretion following mild emotional stimuli, Neuroreport, 6 (1995) 789–792. Moody, R.A. Jr., Laugh After Laugh: Healing Power of Humor, Headwater Press, Jacksonville, FL, 1978, 128 pp. Neisser, U. (Ed.), Memory Observed: Remembering in Natural Contexts, Freeman, San Francisco, CA, 1982. Newman, M.G. and Stone, A.A., Does humor moderate the effects of experimentally-induced stress?, Ann. Behav. Med., 18 (1996) 101–109. Philip, D. and Judd, R., Intensive Care For A Broken Heart, Bitan Modan, Zmora, Tel-Aviv, 1982, 245 pp. Pilowsky, I., Comments on ‘Chronic pain as a variant of depressive disease: The pain-prone disorder’, J. Nerv. Ment. Dis., 170 (1982) 407– 408.
M. Weisenberg et al. / Pain 76 (1998) 365–375 Pilowsky, I., Affective disorders and pain. In: R. Dubner, G.F. Gebhart and M.R. Bond (Eds.), Proceedings of the Fifth World Congress on Pain: Pain Research and Clinical Management, Vol. 3, Elsevier, Amsterdam, 1988, pp. 263–275. Price, D.D., Hypnotic analgesia: psychological and neural mechanisms. In: J. Barber (Ed.), Hypnosis and Suggestion in the Treatment of Pain, Norton, New York, 1996, pp. 67–84. Price, D.D., Barrell, J.J. and Gracely, R.H., Psychophysical analysis of experiential factors that selectively influence the affective dimension of pain, Pain, 8 (1980) 137–150. Rollman, G.B., Cognitive effects in pain and pain judgments. In: D. Algom (Ed.), Psychophysical Approaches to Cognition, Elsevier Science, Amsterdam, 1992, pp. 515–574. Rollman, G.B. and Harris, G., The detectability, discriminability, and perceived magnitude of painful electrical shock, Percept. Psychophys., 42 (1987) 257–258. Shacham, S., Dar, R. and Cleeland, C.S., The relationship of mood state to the severity of clinical pain, Pain, 18 (1984) 187–197. Spielberger, C.D., Gorsuch, R.L. and Lushene, R.E., Manual for the StateTrait Anxiety Inventory, Consulting Psychologist Press, Palo Alto, CA, 1970. Spierings, E.L., Sorbi, M., Haimovitz, B.R. and Tellegen, B., Changes in daily hassles, mood, and sleep in the 2 days before a migraine headache, Clin. J. Pain, 12 (1996) 38–42. Sternbach, R.A., Pain Patients: Traits and Treatment, Academic Press, New York, 1974. Thayer, R.E., Energy, tiredness, and tension effects of a sugar snack versus moderate exercise, J. Pers. Soc. Psychol., 52 (1987) 119–125. Thorson, J.A., A funny thing happened on the way to the morgue: some thoughts on humor and death, and a taxonomy of the humor associated with death, Death Studies, 9 (1985) 201–216.
375
Urba, S.G., Nonpharmacologic pain management in terminal care, Clin. Geriatr. Med., 12 (1996) 301–311. Velten, E., A laboratory task for induction of mood states, Behav. Res. Ther., 6 (1968) 473–482. Weisenberg, M., Pain and pain control, Psychol. Bull., 84 (1977) 1008– 1044. Weisenberg, M., Cognitive aspects of pain. In: P.D. Wall and R. Melzack (Eds.), Textbook of Pain, 3rd edn., Churchill Livingstone, Edinburgh, 1994, pp. 275–289. Weisenberg, M., Wolf, Y., Mittwoch, T., Mikulincer, M. and Aviram, O., Subject versus experimenter control in the reaction to pain, Pain, 23 (1985) 187–200. Weisenberg, M., Schwarzwald, J. and Tepper, I., The influence of warning signal and cognitive preparation on the aversiveness of cold-pressor pain, Pain, 64 (1996a) 379–385. Weisenberg, M., Tepper, I. and Schwarzwald, J., Humor as a cognitive technique for increasing pain tolerance, Pain, 63 (1996b) 207–212. Weisz, H., The Influence of Cognitive Preparation, Perceived Self-efficacy, Warning Signal Timing and Recovery Time, on the Aversiveness of Cold-pressor Pain, M.A. thesis, Bar-Ilan University, Ramat-Gan, Israel, 1997, 95 pp. Zelman, D.C., Howland, E.W., Nichols, S.N. and Cleeland, C.S., The effects of induced mood on laboratory pain, Pain, 46 (1991) 105– 111. Ziv, A., The Psychology of Humor, Yahdav Press, Tel-Aviv, Israel, 1981, 247 pp. Zuckerman, M. and Lubin, B., Manual for the Multiple Affect Adjective Checklist, Educational and Industrial Testing Service, San Diego, CA, 1965.
The influence of film-induced mood on pain perception Matisyohu Weisenberg*, Tal Raz, Tamar Hener Department of Psychology, Bar-Ilan University, Ramat-Gan, Israel Received 5 August 1997; received in revised form 17 March 1998; accepted 27 March 1998
Abstract It has been shown that a person’s mood can influence pain tolerance. Films have been used as a means of inducing a desired mood. The effect on pain perception of film type and film length to induce mood was investigated. Previous research with brief humorous films had not indicated any unique advantage of humor over distraction approaches. Other recent research had indicated that after exposure to film stimulation there is a need to wait approximately 40 min before physiological changes can be obtained. Thus, the present study varied both film type and length and introduced a 30-min waiting period following the mood induction via film prior to exposure to cold-pressor pain. Two hundred subjects in nine different groups participated in the study. Three types of films were used: (1) humorous, (2) holocaust, (3) neutral. Three lengths of each type were also used: 15 min, 30 min, and 45 min. In addition, a tenth no-film group served as a control for the effects of a film. Each subject was given a baseline trial of cold-pressor pain, a trial immediately following the film and a trial 30 min later. Results indicated an advantage in increased pain tolerance for the humorous film and an increased pain tolerance for the longer film regardless of type only after the 30-min waiting period. Results were discussed from a pain theoretical perspective with emphasis placed on returning to psychological manipulations of the sensory aspects of pain and not just the cognitive/emotional/motivational dimensions. 1998 International Association for the Study of Pain. Published by Elsevier Science B.V. Keywords: Humor; Mood; Sensory effects; Cognitive effects
1. Introduction The purpose of the present study was to assess the effects on pain perception of film-induced mood as a function of film type and film length. The long-term goal is to develop techniques that are scientifically and theoretically sound and applicable to the clinical setting. Mood, and especially depression, has been shown to have an influence on pain perception and pain tolerance. The association of pain and depression has a long history in the pain control literature. Sternbach (1974) reviewed studies that indicated that pain may occur in place of depression and that use of antidepressant medication can alleviate the pain. Blumer and colleagues (Blumer and Heilbronn, 1982; Blumer et al., 1982) presented evidence that chronic psychogenic pain patients appear to suffer from depression. The evidence included psychodynamic factors as well as biological markers. These patients responded well to anti-
* Corresponding author. Tel.: +972 3 5318539; fax: +972 3 5350267.
depressant medication. However, even in 1982, the connection of pain and depression was not received without criticism. Merskey (1982) and Pilowsky (1982), although acknowledging that pain and depression do occur jointly, felt that it would be a mistake to view chronic pain only from the perspective of depression. The literature on pain and depression is vast. In a Medline search from 1983 to 1997, 3232 citations were noted. Indepth review of this entire literature is beyond the scope of this introduction. More recent reviews of the literature indicate that depression could lead to pain, pain could lead to depression, and it is possible that both pain and depression use the same mechanisms, especially the serotonin pathways (Pilowsky, 1988; Gamsa and Vikis-Freibergs, 1991; Craig, 1994). The positive effects of antidepressant medications such as amitriptyline have been attributed to the elevation of the depressive mood of the patient (Bryson and Wilde, 1996). However, Harrison et al. (1997) indicated that three months of treatment with antidepressant medication reduced pain severity and distress in nondepressed patients. This latter finding is consistent with the idea that
0304-3959/98/$19.00 1998 International Association for the Study of Pain. Published by Elsevier Science B.V. PII S0304-3959 (98 )0 0069-4
366
M. Weisenberg et al. / Pain 76 (1998) 365–375
the effectiveness of antidepressant medication in the treatment of chronic pain may not be due to the reduction of depression. Despite the findings that pain and depression are not always directly linked, there are enough findings to indicate a meaningful relationship of pain and depression. For example, Krittayaphong et al. (1996) reported that depressed compared to nondepressed heart patients complained more of anginal pain. In chronic low back pain depression is also very prevalent (cf. Gallagher et al., 1995). Overall, negative mood has been found to be related to pain severity (Shacham et al., 1984). Mood states of tension, irritability, depression and tiredness have been found to increase two days before migraine headache attacks (Spierings et al., 1996). Mood disturbance scores and reports of pain in oncology patients were found to be related (Glover et al., 1995). Even in infancy, mother’s mood ratings of their children were found to predict how the infants would react following blood sampling (Bonichini and Benini, 1995). As reviewed earlier (Weisenberg et al., 1996b), the use of humor has a long history. It has been seen as a means to deal with frightening situations (Dixon, 1980; Thorson, 1985), anxiety reduction (Cohen, 1989), anger and depression reduction (Philip and Judd, 1982), and as a means of producing an overall atmosphere of relaxation and comfort for terminal patients (Urba, 1996). Humor is said to produce a variety of physiological effects from increased catecholamine and endorphin levels (Haig, 1988) to reduced muscle tension (Moody, 1978). In a recent study, Newman and Stone (1996) were able to demonstrate that the production of humor while being exposed to an aversive stimulus yielded lower negative affect, lower tension, and reduced psychophysiological reactivity. Interestingly, with all the qualities attributed to humor, there have been few controlled studies in the application of humor to pain reduction and tolerance. The previous research of Weisenberg et al. (1996b) was not able to demonstrate a unique advantage in the use of humor above and beyond that of distraction. Study participants were briefly exposed to filmed material during which they were asked to immerse their arms in water that was cooled to 1°C. They continued watching the films while receiving the stimulation. Recent work, that has demonstrated that filmed materials can influence the immune system, has argued that at least 40–45 min are required for the stimulus to produce the desired effects (Mittwoch-Jaffe et al., 1995). This work has suggested that the Weisenberg et al. (1996b) study of humor may not have been adequate from a time perspective in order to demonstrate some novel aspects of humor. On the basis of these previous studies it might be possible to conclude that shorter exposure times may lead to a distraction effect, while longer exposure times may show outcomes that are more uniquely related to humor. This report is an extension of our previous work on the use of humor and filmed materials as a means of
increasing pain tolerance (Weisenberg et al., 1996b). The length of the mood-induction stimuli was varied and a delayed test of their effects was introduced. Although the present study used films to induce mood, there have been many other techniques used. One of the most widely used approaches to induce a given mood, as seen in the experimental literature, is the Velten procedure (Velten, 1968). In this procedure subjects are given a number of statements to induce a specific mood such as euphoria or depression. Meta-analysis of many studies has indicated that the procedure is valid (Larsen and Sinnett, 1991). Zelman et al. (1991) used the Velten procedure to induce depressive, neutral or euphoric states. Subjects were given cold-pressor pain. Pain tolerance, but not pain ratings, was affected. Subjects in the euphoric group increased, while subjects in the depressive group decreased, tolerance time in comparison to the neutral group. By contrast, contrary to Zelman et al. (1991), Berntzen and Sen (1986) using the Velten procedure found that the depressive but not the positive mood induction led to an increase in cold-pressor tolerance while both conditions led to an increased pain rating. Aside from the issues of what subjects actually experience when the Velten induction is used, research has indicated that the effects of the Velten induction do not last more than a very short time, approximately 10 min, and the effects can be dissipated easily by intervening tasks (Frost and Green, 1982; Isen and Gorgolione, 1983). As the ultimate goal is application to a clinical setting, it was felt that the use of filmed materials to induce mood would be more appropriate. This decision was strengthened by the recent review of mood-induction procedures (GerrardsHesse et al., 1994) that rated films as the first method of choice for the induction of elation and depression. One of the goals of this study was to assess the effect of the film mood induction after 30 min of waiting. Would the effect of the mood induction, unlike the Velten procedure, be longerlasting and hence more applicable in a clinical setting? To summarize, the purpose of this study was to assess the effects on pain perception of film-induced mood as a function of film type and film length. A further goal of this study was to assess the effect of the mood induction after 30 min. The ultimate goal is to lead to techniques that could be used in a clinical setting.
2. Method 2.1. Subjects Two hundred volunteer, paid subjects (100 males and 100 females) aged 18–36 years (median = 23) recruited by posters participated in the laboratory study. The main inclusion or exclusion criterion was the subject’s health status as determined by the health questionnaire. All subjects were told that the cold-pressor stimulus could cause pain. They were told that they could quit at any time and were asked to
367
M. Weisenberg et al. / Pain 76 (1998) 365–375
sign informed consent agreements. One hundred and eighty subjects were shown a film while 20 subjects experienced the pain stimuli but did not view a film. An additional 29 subjects started the study but were discontinued, as they had reached the ceiling maximum of 4 min of cold-pressor stimulation in the first trial and could not show any additional increase in tolerance. Subjects were randomly assigned to the different groups. 2.2. Film stimuli Three types of films were chosen: (1) a humorous film to induce a positive mood, (2) a holocaust film to induce a negative mood, and (3) a neutral film on alligators. Each film type was shown for either 15, 30 or 45 min. The negative stimulus was taken from the study of Mittwoch-Jaffe et al. (1995) that demonstrated a physiological influence on parameters of the immune system as a result of watching the film. Each film was rated by 10 judges for a total of 90 different judges (see Table 1). Judges were recruited in a similar manner as the subjects and were of approximately the same age. Films were rated from 1–5 for the level of interest (1 = very interesting, 5 = very boring), for the level of mood (1 = very happy, 5 = very sad), and for the level of the subject’s mood as a consequence of viewing the film (1 = very happy, 5 = very sad). Two-way analysis of variance (3 types of film × 3 lengths of film) indicated that for interest, the films did not yield differences for type of film (F(2,81) = 1.33, P . 0.05), nor for length of film (F (2,81) = 0.41, P . 0.05), nor for the interaction of type of film by length (F(4,81) = 0.90, P . 0.05). Two-way analysis of mood ratings of the films yielded significance for type of film (F(2,81) = 502.75, P , 0.001). Multiple contrast analysis by the Scheffe method indicated that the humorous film was judged as happier than the neutral film that in turn differed from the holocaust film. The holocaust film, in turn, was judged as sadder than either the humorous or neutral film. Length of film was not significant (F(2,81) = 2.18, P . 0.05) nor was the interaction of type of film by length (F(4,81) = 1.80, P . 0.05). Analysis of variance of the induced mood of the judges indicated significant differences for the type of film (F(2,81) = 144.38, P , 0.001). Multiple contrast analysis by Scheffe indicated that the humorous
film yielded a happier mood than the other two films, while the holocaust film yielded a sadder mood than the other two films. No differences of induced mood were obtained for length of film (F(2,81) = 2.36, P . 0.05) nor for the interaction of type of film by length (F(4,81) = 0.53, P . 0.05). During the study itself, additional ratings of film mood and induced personal mood were obtained from participants (Table 2). Analysis of variance (3 types of films × 3 levels of length) indicated that the film mood ratings differed as a function of type of film (F (2,171) = 447.63, P , 0.001). Multiple contrast analysis by Scheffe indicated that the each film significantly differed from the other in the desired direction. Neither film length (F(2,171) = 0.45, P . 0.05) nor the interaction of film type by length (F(4,171) = 1.27, P . 0.05) were significant. The induced personal mood ratings were also subjected to analysis of variance (3 types of films × 3 levels of length). Results indicated that the induced personal mood ratings differed as a function of type of film (F(2,171) = 124.62, P , 0.001). Multiple contrast analysis by Scheffe indicated that each film significantly differed from the other in the desired direction. Neither film length (F(2,171)= 0.14,P . 0.05) nor the interaction of film type by length (F(4,171) = 0.90, P . 0.05) were significant. Following the second immersion, the groups still showed significant differences in the desired direction (F(2,171) = 30.73, P , 0.001). Multiple contrast analysis by Scheffe indicated that the types of films each differed from each other. Following the third immersion, the mood ratings did not differ from each other as a function of type of film. 2.3. Pain stimuli Cold-pressor was chosen as the pain stimulus as it has been used in many of the cognitive studies and there are readily available norms (Hilgard, 1969). The water was maintained at 1°C by an immersion cooler and kept in constant circulation by an underwater mixer. On instruction, the subject immersed his/her arm in the water by pressing down on the arm rest on which the subject kept his/ her left arm, simultaneously starting a clock to measure
Table 1 Mean ratings by judges of the mood and interest level of the films and the induced personal mood the films produced Type of film Humorous
Film interest Film mood Personal mood
Neutral
Holocaust
15 min
30 min
45 min
15 min
30 min
45 min
15 min
30 min
45 min
2.70 2.20 2.50
2.55 2.00 2.11
2.80 2.00 2.20
2.50 3.00 3.00
2.09 2.90 2.09
2.60 3.00 3.00
2.50 4.60 4.40
2.60 4.50 4.10
2.30 4.90 4.40
Interest: 1 = very interesting, 5 = very boring. Mood: 1 = very happy, 5 = very sad. For each cell n = 10.
368
M. Weisenberg et al. / Pain 76 (1998) 365–375
insertion time. The maximum time in the water was limited to 240 s. 2.4. Skin resistance Skin resistance response (SRR) is a commonly used measure of sympathetic arousal in pain studies (cf. Arntz and Lousberg, 1990; Al Absi and Rokke, 1991; Weisenberg et al., 1996a). SRR electrodes were placed on the index and middle finger of the right hand. SRR was measured via an Atlas Scanmaster 8600-3 computer physiograph. Samples of SRR in ohms (Q) were obtained prior to immersion and for the highest point reached every 10 s while the arm was in the water. 2.5. Verbal measures The State-Trait Anxiety Inventory (STAI), developed by Spielberger et al. (1970), is a 40-item measure of how anxious the subject felt at the moment and how anxious he/she feels generally. Two scores are derived: (1) State anxiety, and (2) Trait anxiety. Scores had a possible range from 20 to 80 for each of the anxiety scales. For this study the reliability for State anxiety was a = 0.87 and for Trait anxiety a = 0.85. The Humor Questionnaire developed by Ziv (1981) is a 14-item scale that measures appreciation of humorous situations and ability to cause others to laugh. Three scores can be derived: (1) General score which is the sum of responses to the entire scale, (2) Humor appreciation which is the sum of responses to the first seven items, and (3) Humor production which is the sum of the last seven items. Overall reliability of the scale as obtained in this study was a = 0.80. The perceived self-efficacy of pain control is a 14-item measure that refers to the judgment a person makes concerning his ability to execute certain actions to deal with his/ her environment (Bandura, 1982; Mittwoch et al., 1990). The score is the sum of the responses to the entire scale. In this study it referred to the subject’s perceived ability to control pain associated with cold water. The scale was administered prior to the cold-pressor stimulation and as part of the post-experimental questionnaire. The scale reliability for this study was a = 0.92.
Pain and anxiety ratings were obtained immediately following the removal of the subject’s arm from the water. Subjects were asked to rate the pain and present feelings of anxiety on visual analog scales as used in earlier studies (Weisenberg et al., 1985; Mittwoch et al., 1990). It is possible to obtain pain ratings during the stimulation itself. This was not done so that the act of measurement in and of itself should not interfere with the experimental results as can occur (Weisz, 1997). In addition, the outcome of the study was based on a number of additional measures such as duration in water, skin resistance, etc. Mood ratings were obtained following the subject’s viewing of the films and following the subject’s immersion in the water. Two measures were used: (1) a visual analog scale of mood in which ratings of 1 = very happy and 5 = very sad; and (2) the scale to measure depressive mood (Zuckerman and Lubin, 1965). This scale consisted of 34 adjectives in which 22 words described depressive feelings while 12 described satisfied feelings. The depressive items and the non-endorsed satisfied items are added together to yield a total score. Reliability for this study was a = 0.78. The post-experimental questionnaire was designed to measure the subject’s ratings of task importance, perceived success in coping and ratings of the helpfulness of the films. 2.6. Procedure After obtaining an informed consent agreement and after health screening, each subject was asked to complete the STAI, the Humor Questionnaire, and the self-efficacy questionnaire. Subjects were told that we were interested in studying the relationship between a person’s mental status and his physiological reactions. As part of the study he/she would be asked to respond to a number of questionnaires, have electrodes attached, be shown a film (for the film conditions), be asked to immerse an arm in cold water that some people feel is painful but not dangerous. The subject was then seated in an electrically isolated booth where electrodes were attached. Five minutes of relaxation were given to permit the subject to adjust to his/her surroundings and to permit the experimenter to calibrate the polygraph. The subject listened to pre-recorded instructions. At the
Table 2 Mean subject ratings of film mood and induced personal mood obtained during the study Time of rating
Type of film Humorous
Following film Following film After immersion 2 After 30-min wait
Film mood Personal mood Personal mood Personal mood
Neutral
Holocaust
15 min
30 min
45 min
15 min
30 min
45 min
15 min
30 min
45 min
2.25 2.40 2.60 2.85
2.05 2.25 2.40 2.65
2.20 2.20 2.50 2.95
2.90 2.75 2.55 2.60
2.95 3.00 2.65 2.75
2.65 2.80 2.80 2.85
4.85 3.90 3.15 2.80
4.80 3.90 3.30 3.05
4.90 4.00 3.40 2.95
Mood: 1 = very happy, 5 = very sad. For each cell n = 20.
M. Weisenberg et al. / Pain 76 (1998) 365–375
369
Fig. 1. Mean time (s) hand in water as a function of type of film. Analysis indicated that the immersion after 30 min yielded a significant difference between films. As can be seen, the humorous film showed a continuous increase in pain tolerance as compared to the others.
end of relaxation, the subject was asked to insert his/her arm into the water and to keep it there until (s)he felt (s)he could no longer do so. For all immersions the experimenter limited the time to 4 min without informing the subject. After the arm was removed from the water, subjects were asked to rate the pain, anxiety during immersion, and present mood. At this point, for the film conditions, a movie was shown appropriate to the group in which the subject belonged. This was followed by mood ratings. For the no-film group, in place of the film, subjects were asked to wait while the apparatus was being recalibrated. Following a 30-min wait, for the no-film group, mood ratings were obtained. No-film subjects were once more asked to insert his/her arms in the water. After removal of the arm from the water, another rating of pain, anxiety and mood was obtained. Following the second immersion, film-group subjects were asked to wait while recalibration took place. This was for 30 min. To assess the effect of the boredom of waiting, half of the subjects were kept occupied by being asked to read neutral material. No differences were obtained for the two waiting groups and hence all results used the combined waiting data. Mood ratings were obtained at the end of the waiting period. A third immersion followed the waiting period. Once more ratings of pain, mood and anxiety were obtained. The post-experimental questionnaire and subject debriefing took place outside the experimental booth.
from each other prior to the experimental manipulation. Therefore, subjects in the different groups should not have differed on measures of mood nor on the reactions to the initial cold-pressor experience. To reduce influences of differences on these initial starting point, analysis of covariance was used. To eliminate the effects of differences in mood with which subjects may have come to the study, the Zuckerman and Lubin (1965) depressive mood ratings were held constant for each immersion. For the second and third cold-pressor experiences, duration of the first immersion also was added as a covariate as this starting point should not have been different between groups. The basic statistical analysis was a 3 (type of film) × 3 (film length) × 2 analysis of covariance (ANCOVA) 3.1. Duration
3. Results
For the groups that viewed a film, inspection of the duration data indicated that there were instances in which the standard deviations were larger than the means. To reduce the possible effects of this problem, a logarithmic transformation of the data was used in all analyses of the duration scores.1 For the first and second immersions, no significant differences were obtained. For the third immersion, with the first immersion as a covariate, a significant difference was obtained for the type of film (F(2,169) = 3.60, P = 0.02). Analysis by the Scheffe indicated that the humorous film yielded a higher duration in water as compared with the other two that did not differ from each other (Fig. 1). In addition, a significant result was also obtained for film length (F(2,169) = 2.90, P = 0.05) (Fig. 2). Analysis by
The analyses of the data were based on the assumption that the subjects in the different conditions did not differ
1 Although analysis of the data without transformation yielded even more powerful effects, it was felt that this would be problematic in terms of the statistical assumptions.
370
M. Weisenberg et al. / Pain 76 (1998) 365–375
Fig. 2. Mean time (s) hand in cold water as a function of viewing time. Analysis indicated that the 45-min longer viewing time yielded significantly higher pain tolerance.
the Scheffe indicated that immersion time was longer for the 45-min film than for either the 30- or 15-min films that did not differ from each other. None of the interactions reached a level of significance. For all of the analyses, no differences were obtained as a function of sex. To assess the effect of viewing a film, the nine film groups were collapsed into three according to type of film. They were compared with the no-film control group in a one way ANCOVA with the Zuckerman and Lubin ratings held constant for the first immersion. For the second and third immersions, the first immersion duration also was added as a covariate. No differences were obtained for the first or second immersions. For the third immersion, a significant
difference was obtained (F(3,194) = 3.38, P = 0.01). Scheffe analysis indicated that the no-film control group yielded the lowest duration in the water. 3.2. Pain ratings For the groups that viewed a film (see Table 3), no significant differences were obtained for the first and second immersions. For the third immersion, with the Zuckerman and Lubin ratings and the first immersion as covariates, no significant difference was obtained. When the Zuckerman and Lubin ratings and the second immersion pain ratings were used as covariates, a significant difference was obtained for the type of film (F(2,170) = 3.34, P = 0.03).
Table 3 Mean pain ratings and standard deviation following arm immersion in water by length and type of film Immersion trial 1
2
3
Length of film (min) 15 30 45 Total 15 30 45 Total 15 30 45 Total
Type of film
Total
Holocaust
Neutral
Humorous
69.62 66.82 67.25 67.90 67.25 63.75 61.90 64.30 64.30 68.50 61.75 64.85
60.82 64.17 61.18 62.06 52.00 57.25 60.50 56.55 51.75 58.15 60.75 56.88
69.62 62.75 72.19 68.18 67.45 55.50 71.00 64.65 61.70 52.15 62.75 58.86
(19.70) (15.91) (16.26) (17.12) (17.28) (18.69) (16.49) (17.36) (19.62) (20.26) (19.28) (19.59)
(20.53) (15.35) (22.69) (19.48) (22.84) (20.34) (24.16) (22.40) (22.25) (22.00) (22.90) (22.33)
Scores ranged from 0 = no pain to 100 = extreme pain. For each cell n = 20.
(18.39) (15.25) (16.42) (16.91) (17.86) (20.89) (13.82) (18.90) (19.36) (19.85) (17.65) (19.26)
No film
66.69 (19.68) 64.58 (15.32) 66.87 (18.93) 69.48 (18.41) 62.23 (20.50) 60.12 (19.78) 64.46 (18.95) 64.21 (19.09) 59.25 (20.83) 59.60 (21.48) 61.75 (19.74) 73.25 (16.40)
371
M. Weisenberg et al. / Pain 76 (1998) 365–375
Scheffe analysis indicated that the humorous film showed a reduced pain rating from immersion 2 to immersion 3 as compared with the other two film groups that did not change. No significant differences were obtained for sex, film length nor for any of the interactions. To assess the effect of viewing a film, the nine film groups were collapsed into three according to type of film. They were compared with the no-film control group in a one-way ANCOVA with the Zuckerman and Lubin ratings held constant for the first immersion. For the second and third immersions, the first immersion pain rating also was added as a covariate. No differences were obtained for the first or second immersions. For the third immersion, a significant difference was obtained (F(3,194) = 3.72, P = 0.01). Scheffe analysis indicated that the no-film group showed the highest pain rating compared to the other film groups that did not differ from each other. 3.3. SRR For the groups that viewed a film, ANCOVA was conducted for SRR measures obtained for the highest level reached in the first 10 s for each immersion with the Zuckerman and Lubin (1965) depressive mood ratings held constant for the first immersion (see Table 4). For the first immersion, no significant differences were obtained for type of film nor for film length. A sex difference was obtained (F(1,150) = 5.28, P = 0.02). Women yielded a higher level of SRR than men (M = 3291.8, M = 2463.6, for women and men, respectively). For the second immersion in addition to the Zuckerman and Lubin ratings, the SRR of the first immersion was also added as a covariate. Significant differences were obtained for film length (F(2,152) = 3.03, P = 0.05). Scheffe analysis indicated that the 45-min film yielded the lowest level of SRR. No differences were obtained for the type of film nor for the interactions. Here, too, a significant sex difference was obtained (F(1,143) = 3.62, P = 0.05). Women yielded a
higher level of SRR than men (M = 2353.6, M = 1986.5, for women and men, respectively). For the third immersion, with the Zuckerman and Lubin ratings and the first immersion SRR as covariates, no significant difference was obtained. When the Zuckerman and Lubin ratings and the second immersion SRR were used as covariates a significant difference was obtained for the type of film (F(2,157) = 3.47, P = 0.03). Scheffe analysis indicated that the neutral film showed the lowest SRR as compared with the other two film groups. No significant differences were obtained for sex, film length nor for any of the interactions. To assess the effect of viewing a film, the nine film groups were collapsed into three according to type of film. They were compared with the no-film control group in a one way ANCOVA with the Zuckerman and Lubin ratings held constant for the first immersion. For the second and third immersions, the first immersion SRR also was added as a covariate. No differences were obtained for the first, second or third immersions. 3.4. Anxiety ratings For the groups that viewed a film, no significant differences were obtained for the first and second immersions. For the third immersion, with the Zuckerman and Lubin ratings and the first immersion anxiety ratings as covariates, no significant main effects were obtained. However, a significant interaction of type of film and film length was obtained (F(4,169) = 3.15, P = 0.01). Further analysis by the Duncan test indicated that the anxiety ratings for the neutral film were lowest for the 15-min length compared to the 30and 45-min films (M = 6.58, M = 20.85, M = 18.99, for the 15-, 30- and 45-min films, respectively). For the humorous (M = 9.92, M = 18.99, M = 21.91, for the 15-, 30- and 45-min films, respectively) and for the holocaust films (M = 17.71, M = 13.30, M = 18.10, for the 15-, 30- and 45-min films, respectively), no differences were obtained.
Table 4 Mean SRR (Q) and standard deviation during arm immersion in water by length and type of film Immersion trial 1
2
3
Length of film (min) 15 30 45 Total 15 30 45 Total 15 30 45 Total
For each cell n = 20.
Type of film
Total
Holocaust
Neutral
Humorous
3066 3786 2786 3213 2246 2635 1657 2208 2680 2823 2472 2156
3279 2440 2869 2863 2902 2162 1882 2302 1915 1824 2256 1997
2285 1960 3229 2491 2162 1842 2020 2002 2372 2030 2078 2665
(2370) (3375) (2544) (2768) (1372) (1937) (997) (1534) (2174) (2295) (2561) (1619)
(2817) (2417) (2464) (2536) (2512) (1602) (1316) (1878) (1154) (1536) (1314) (1340)
(1333) (1063) (2311) (1734) (2126) (1597) (947) (1585) (1964) (1741) (1116) (2303)
No film
2876 (2240) 2729 (2534) 2961 (2399) 2810 (1817) 2433 (2036) 2206 (1717) 1866 (1091) 2208 (2267) 2323 (1814) 2215 (1893) 2258 (1712) 2007 (1723)
372
M. Weisenberg et al. / Pain 76 (1998) 365–375
To assess the effect of viewing a film, the nine film groups were collapsed into three according to type of film. They were compared with the no-film control group in a one way ANCOVA with the Zuckerman and Lubin ratings held constant for the first immersion. For the second and third immersions, the first immersion anxiety ratings were also added as covariates. No significant differences were obtained. 3.5. Perceived self-efficacy Scores on the first measure of self-efficacy were divided at the median to permit an assessment for high and low selfefficacy. Data for each of the dependent variables of duration in water, pain ratings, SRR, and anxiety ratings were subjected to a 2 (high, low self-efficacy) × 3 (type of film) × 3 (length of film) ANCOVA with the Zuckerman and Lubin scale as a covariate on the first immersion and the results of the first immersion as an additional covariate for the second and third immersions. For the duration in water, no significant main effects or interactions were obtained. However, the overall correlation of self-efficacy and duration in water, although low, was significant (r = 0.20, P , 0.05). For pain ratings a significant difference for self-efficacy was obtained for the third immersion (F(1,160) = 6.49, P = 0.01). The high self-efficacy group yielded lower pain ratings (M = 56.46) than the low self-efficacy group (M = 63.51). For SRR a significant difference was obtained for the second immersion (F(1,143) = 5.19, P = 0.02). The high self-efficacy subjects yielded a lower SRR (M = 1887.2) compared to the low self-efficacy group (M = 2337.0). For anxiety ratings, a significant difference was obtained on the first immersion for self-efficacy (F(1,161) = 6.75, P = 0.01). High self-efficacy subjects rated themselves as less anxious (M = 18.10) than their low counterparts (M = 27.47). Overall, a significant low inverse correlation was obtained between self-efficacy and anxiety ratings (r = − 0.19, P , 0.05). The measure of self-efficacy in the post-experimental questionnaire was analyzed in a similar manner as the first self-efficacy measure with the first measure used as a covariate. No significant differences were obtained for type or length of film. 3.6. Humor Scores on the humor measures were divided at the median to produce high- and low-humor groups. Data for each of the dependent variables of duration in water, pain ratings, SRR, and anxiety ratings were subjected to a 2 (high, low self-efficacy) × 3 (type of film) × 3 (length of film) ANCOVA with the Zuckerman and Lubin scale as a covariate on the first immersion and the results of the first immersion as an additional covariate for the second and third immersions.
No significant differences were obtained for the different measures of humor (general, humor appreciation, humor production). 3.7. State-Trait Anxiety Scores on the State-Trait Anxiety Inventory were divided at the median separately for state and trait to permit an assessment for high and low anxiety. Data for each of the dependent variables of duration in water, pain ratings, SRR, and anxiety ratings were subjected to a 2 (high, low selfefficacy) × 3 (type of film) × 3 (length of film) ANCOVA with the Zuckerman and Lubin scale as a covariate on the first immersion, and the results of the first immersion as an additional covariate for the second and third immersions. The only significant difference for state anxiety was obtained for the rating of anxiety following the first immersion (F(1,161) = 22.85, P , 0.00). Lower anxiety ratings were obtained for the low state anxiety subjects (M = 14.39) compared to the high state anxiety subjects (M = 32.83). For trait anxiety, a significant result was obtained for the second immersion anxiety ratings (F(1,160) = 4.50, P = 0.03). Low trait anxiety subjects yieled lower anxiety ratings. (M = 14.82) compared to high trait anxiety subjects (M = 19.99). 3.8. Post-experimental questionnaire The variables of the post-experimental questionnaire, perceived task importance, perceived success in coping and perceived helpfulness of the films were subjected to a 3 (type of film) × 3 (length of film) ANOVA. No significant difference was obtained for perceived task importance or perceived success in coping. For perceived helpfulness, a significant result was obtained for type of film F(2,126) = 3.76, P = 0.02). Duncan analysis indicated that the neutral film was judged as less helpful (M = 1.33) than the humorous (M = 2.10) or the holocaust film (M = 2.37).
4. Discussion The purpose of this study was to assess the effects on pain perception for film-induced mood as a function of film type and film length. Results indicated a significant advantage for the humorous film that was obtained only after the 30-min waiting period. This was reflected in the increased pain tolerance time and in the pain ratings. In addition, there appears to be an advantage to the length of the film, regardless of content as seen by the increased duration in the cold water and by the lower level of SRR. The no-film group, in turn, showed less tolerance and gave higher pain ratings than the film groups. Once more, these effects were not immediately apparent. They occurred only after the 30min wait. Perceived self-efficacy in pain control yielded
M. Weisenberg et al. / Pain 76 (1998) 365–375
more immediate effects on some measures, anxiety, SRR and pain ratings. The results of this study raise a number of theoretical and practical issues. First is the question as to how to explain that the effects of the induction are obtained only after 30 min of waiting. One possible straightforward explanation can be based on memory and the fading of the memory trace over time. That is, the experimental session itself could have produced an emotional arousal (Weisenberg et al., 1996b). Over time some conditions were more effective and faded less easily than others. It is accepted that emotional memories fade less rapidly than non-emotional memories (Neisser, 1982). The humorous film and the longer films, therefore, may have faded less rapidly in comparison to the other conditions. From another perspective, pain has been viewed as consisting of a sensory component, a cognitive-emotional-motivational component and a central component (cf. Weisenberg, 1977; Melzack, 1986). Most of the psychological approaches have forsaken the sensory aspects of pain and are associated with changes in the cognitive-emotionalmotivational component of pain. The cognitive interventions mainly influence the person by affecting the way the pain is perceived, interpreted or related to rather than affecting the sensory component per se (Weisenberg, 1994). In turn, it is possible to place greater emphasis on the sensory component of pain. Using magnitude estimation procedures, Rollman and Harris (1987) reported on a series of obtained power functions ranging from 1.0 to 3.0. In a recent review, Rollman (1992) has analyzed some of these issues and attempts at separating the sensory and cognitive-emotional-motivational components of pain. Price et al. (1980) attempted to separate the sensory and the affective magnitudes of pain. They were able to do so only up to a point. Scales have been developed to distinguish between the different components of pain and have been used to assess the effects of interventions for pain control (e.g. Gracely et al., 1978). Another recent approach as represented by the functional theory of pain (Algom, 1992) places emphasis on the sensory component of pain. Using the methodology of psychophysics the theory attempts to determine how the sensory aspects of pain are perceived. There is an emphasis on the integration of stimuli from all the different sources that impinge on the individual before the final judgment of painfulness is made. This would also include mental attitude or prior preparation. According to the functional theory, pain perception can be reduced simply because the stimulus is processed by mechanisms unrelated to nociception. Pain perception can be influenced by interacting with other central mechanisms that are of either a cognitive or sensory origin. The final integration of the judgment of pain, according to this theory, deals primarily with the sensory aspects of pain. Rollman (1992) argues that with all the work done to separate the different components of pain, it is a task that
373
is not completely successful. The components of pain appear to be related to one another even though it is possible to place a greater emphasis on one aspect or another. Clark et al. (1989), for example, reported that cancer patients found sensory descriptors to have more emotional qualities than healthy controls. It is possible to speculate and apply these different approaches to the results of the present study as opposed to the earlier work (Weisenberg et al., 1996b). The earlier work in which the film was shown briefly and in which the subject was asked to immerse in cold water during the film was mostly effective as a cognitive distractor, affecting mainly the cognitive/emotional/motivational aspects of pain. In the current study subjects were exposed to longer film presentations and a longer time interval prior to receiving the pain stimulation. During the longer 30-min interval there was time for changes of a physiological nature to occur as described by Mittwoch-Jaffe et al. (1995). Hence, it is possible that the change that occurred, thus influenced the sensory aspect of pain as well as the cognitive–emotional aspects. Interestingly, there is research on exerciseinduced mood that also reported a maximal effect following a 10-min intervention to occur after 30 min (Thayer, 1987). The approach taken here might also help explain why certain of the psychological measures that, a priori, would relate to pain perception were not found to be as closely related to outcome as in prior studies. Firstly, it is interesting to note that the major increase in pain tolerance, was not in accordance with the mood ratings. There is the suggestion of a process that was begun via a mood induction that likely continued even though the original source of the induction was not seen in the mood ratings. Different systems may be functioning at different rates. In the present study, the humor scale did not show any differences. This is consistent with the earlier report of Newman and Stone (1996) who found no differences for both high and low scorers on the humor scale. The measure of self-efficacy of pain control in previous research was found to be more strongly related to outcomes (Weisenberg et al., 1996a). Self-efficacy likely reflects a person’s motivation to perform whatever is being measured. When referring to pain, self-efficacy refers to a willingness to continue or to tolerate the stimulation rather than a skill deficit (Maddux, 1995). In light of the weaker self-efficacy– pain relationship found in this study, it is likely that the cognitive/emotional/motivational aspects of pain played less of a role as compared to the physiological effects on the sensory component of pain. The above analysis implies that the psychological interventions for pain may be classified as affecting mainly different aspects of pain. Up to this point in time, the major emphasis of the psychological approach has been on techniques that reduce anxiety and increase motivation to accept the pain stimulation. Thus, for example, the appropriate preparation of mothers prior to birth emphasizes anxiety reduction and other cognitive techniques. It has been
374
M. Weisenberg et al. / Pain 76 (1998) 365–375
reported to reduce perceived pain by as much as 30% (Melzack, 1984). If techniques could be added to influence more effectively the sensory component of pain, perhaps the 30% could be raised to 50% or higher. In addressing the sensory aspects more directly, the major exception has been the use of hypnosis according to those theorists who do not view it as yet another cognitive technique (cf. Price, 1996). Fernandez and Turk (1992) have argued that these separate dimensions of pain exist but are related. Be that as it may, in the spirit of psychoneuroimmunology (Ader et al., 1991), perhaps it is time to once more turn to a greater emphasis on psychological approaches that will have a greater effect on the sensory dimensions of pain.
Acknowledgements This research was supported by a grant from the Koret Foundation. Gratitude is expressed to Yossi Gadot for his technical assistance in the conduct of this study.
References Ader, R., Felton, D.L. and Cohen, N. (Eds.), Psychoneuroimmunology, 2nd edn., Academic Press, San Diego, CA, 1991. Al Absi, M. and Rokke, P.D., Can anxiety help us tolerate pain?, Pain, 46 (1991) 43–51. Algom, D., Psychophysical analysis of pain: a functional perspective. In: H.G. Geissler, S.W. Link and J.T. Townsend (Eds.), Cognition, Information Processing and Psychophysics: Basic Issues, Erlbaum, Hillsdale, NJ, 1992, pp. 267–291. Arntz, A. and Lousberg, R., The effects of underestimated pain and their relationship to habituation, Behav. Res. Ther., 28 (1990) 15–28. Bandura, A., Self-efficacy mechanism in human agency, Am. Psychol., 37 (1982) 122–147. Berntzen, D. and Sen, B., Effects of experimentally induced positive and negative mood on laboratory pain. In: D. Berntzen. (Ed.), Analysis and Management of Experimental and Clinical Pain, University of Trondheim, Trondheim, Norway, 1986, paper IV, pp. 1–15. Blumer, D. and Heilbronn, M., Chronic pain as a variant of depressive disease, J. Nerv. Ment. Dis., 170 (1982) 381–406. Blumer, D., Zorick, F., Heilbronn, M. and Roth, T., Biological markers for depression in chronic pain, J. Nerv. Ment. Dis., 170 (1982) 425– 428. Bonichini, A. and Benini, F., Pain in infancy: individual differences, Percept. Motor Skills, 18 (1995) 142. Bryson, H.M. and Wilde, M.I., Amitriptyline. A review of its pharmacological properties and therapeutic use in chronic pain states, Drugs Aging, 8 (1996) 459–476. Clark, W.C., Ferrer-Brechner, T., Janal, M.N., Carroll, J.D. and Yang, C., The dimensions of pain: A multidimensional scaling comparison of cancer patients and healthy volunteers, Pain, 37 (1989) 23–32. Cohen, M.M., The Influence of Active Humor on the Level of Examination Performance, M.A. thesis, Tel-Aviv University, Tel-Aviv, Israel, 1989, 188 pp. Craig, K.D., Emotional aspects of pain. In: P.D. Wall and R. Melzack (Eds.), Textbook of Pain, 3rd edn., Churchill Livingstone, Edinburgh, 1994, pp. 261–274. Dixon, N.F., Humor: A cognitive alternative to stress? In: I.G. Sarason and C.D. Spielberger (Eds.), Stress and Anxiety, Vol. 7, Hemisphere Corp., Washington, DC, 1980, pp. 282–289.
Fernandez, E. and Turk, D.C., Sensory and affective components of pain: separation and synthesis, Psychol. Bull., 112 (1992) 205–217. Frost, R.O. and Green, M.L., Velten mood induction procedure effects: Duration and postexperimental removal, Pers. Soc. Psychol. Bull., 8 (1982) 341–347. Gallagher, R.M., Moore, P. and Chenoff, I., The reliability of depression diagnosis in chronic low back pain. A pilot study, Gen. Hosp. Psychiatry, 71 (1995) 399–413. Gamsa, A. and Vikis-Freibergs, V., Psychological events are both risk factors in, and consequences of, chronic pain, Pain, 44 (1991) 271– 277. Gerrards-Hesse, A., Spies, K. and Hesse, F.W., Experimental inductions of emotional states and their effectiveness: A review, Br. J. Psychol., 85 (1994) 55–78. Glover, J., Dibble, S.L., Dodd, M.J. and Miaskowski, C., Mood states of oncology outpatients: Does pain make a difference?, J. Pain Symptom Managem., 10 (1995) 120–128. Gracely, R.H., McGrath, P. and Dubner, R., Validity and sensitivity of ratio scales of sensory and affective verbal pain descriptors: Manipulation of affect by diazepam, Pain, 5 (1978) 19–30. Haig, R.A., The Anatomy of Humor: Biopsychosocial and Therapeutic Perspectives, C.C. Thomas, Springfield, IL, 1988,. Harrison, S.D., Glover, L., Feinmann, C., Pearce, S.A. and Harris, M., A comparison of antidepressant medication alone and in conjunction with cognitive behavioral therapy for chronic idiopathic facial pain. In: T.S. Jensen, J.A. Turner and Z. Wiesenfeld-Hallin (Eds.), Proceedings of the 8th World Congress on Pain, International Association for the Study of Pain, Seattle, WA, 1997, pp. 663–672. Hilgard, E.R., Pain as a puzzle for psychology and physiology, Am. Psychol., 24 (1969) 103–113. Isen, A.M. and Gorgolione, J.M., Some specific effects of four affectinduction procedures, Pers. Soc. Psychol. Bull., 9 (1983) 136–143. Krittayaphong, R., Light, K.C., Golden, R.N., Finkel, J.B. and Sheps, D.S., Relationship among depression scores, beta endorphin, and angina pectoris during exercise in patients with coronary artery disease, Clin. J. Pain, 12 (1996) 126–133. Larsen, R.J. and Sinnett, L.M., Meta-analysis of experimental manipulations: Some factors affecting the Velten mood induction procedure, Pers. Soc. Psychol. Bull., 17 (1991) 323–334. Maddux, J.E., Self-efficacy theory: An introduction. In: J.E. Maddux (Ed.), Self-efficacy, Adaptation and Adjustment: Theory, Research and Application, Plenum Press, New York, 1995, pp. 3–33. Melzack, R., Neurophysiological foundations of pain. In: R.A. Sternbach (Ed.), The Psychology of Pain, 2nd edn., Raven Press, New York, 1986, pp. 1–24. Melzack, R., The myth of painless childbirth, Pain, 19 (1984) 321– 337. Merskey, H., Comments on ‘Chronic pain as a variant of depressive disease: The pain-prone disorder’, J. Nerv. Ment. Dis., 170 (1982) 409– 411. Mittwoch, T., Weisenberg, M. and Mikulincer, M., The influence of warning signal timing and cognitive preparation on the aversiveness of electric shock, Pain, 42 (1990) 373–381. Mittwoch-Jaffe, T., Shalit, F., Srendi, B. and Yehuda, S., Modification of cytokine secretion following mild emotional stimuli, Neuroreport, 6 (1995) 789–792. Moody, R.A. Jr., Laugh After Laugh: Healing Power of Humor, Headwater Press, Jacksonville, FL, 1978, 128 pp. Neisser, U. (Ed.), Memory Observed: Remembering in Natural Contexts, Freeman, San Francisco, CA, 1982. Newman, M.G. and Stone, A.A., Does humor moderate the effects of experimentally-induced stress?, Ann. Behav. Med., 18 (1996) 101–109. Philip, D. and Judd, R., Intensive Care For A Broken Heart, Bitan Modan, Zmora, Tel-Aviv, 1982, 245 pp. Pilowsky, I., Comments on ‘Chronic pain as a variant of depressive disease: The pain-prone disorder’, J. Nerv. Ment. Dis., 170 (1982) 407– 408.
M. Weisenberg et al. / Pain 76 (1998) 365–375 Pilowsky, I., Affective disorders and pain. In: R. Dubner, G.F. Gebhart and M.R. Bond (Eds.), Proceedings of the Fifth World Congress on Pain: Pain Research and Clinical Management, Vol. 3, Elsevier, Amsterdam, 1988, pp. 263–275. Price, D.D., Hypnotic analgesia: psychological and neural mechanisms. In: J. Barber (Ed.), Hypnosis and Suggestion in the Treatment of Pain, Norton, New York, 1996, pp. 67–84. Price, D.D., Barrell, J.J. and Gracely, R.H., Psychophysical analysis of experiential factors that selectively influence the affective dimension of pain, Pain, 8 (1980) 137–150. Rollman, G.B., Cognitive effects in pain and pain judgments. In: D. Algom (Ed.), Psychophysical Approaches to Cognition, Elsevier Science, Amsterdam, 1992, pp. 515–574. Rollman, G.B. and Harris, G., The detectability, discriminability, and perceived magnitude of painful electrical shock, Percept. Psychophys., 42 (1987) 257–258. Shacham, S., Dar, R. and Cleeland, C.S., The relationship of mood state to the severity of clinical pain, Pain, 18 (1984) 187–197. Spielberger, C.D., Gorsuch, R.L. and Lushene, R.E., Manual for the StateTrait Anxiety Inventory, Consulting Psychologist Press, Palo Alto, CA, 1970. Spierings, E.L., Sorbi, M., Haimovitz, B.R. and Tellegen, B., Changes in daily hassles, mood, and sleep in the 2 days before a migraine headache, Clin. J. Pain, 12 (1996) 38–42. Sternbach, R.A., Pain Patients: Traits and Treatment, Academic Press, New York, 1974. Thayer, R.E., Energy, tiredness, and tension effects of a sugar snack versus moderate exercise, J. Pers. Soc. Psychol., 52 (1987) 119–125. Thorson, J.A., A funny thing happened on the way to the morgue: some thoughts on humor and death, and a taxonomy of the humor associated with death, Death Studies, 9 (1985) 201–216.
375
Urba, S.G., Nonpharmacologic pain management in terminal care, Clin. Geriatr. Med., 12 (1996) 301–311. Velten, E., A laboratory task for induction of mood states, Behav. Res. Ther., 6 (1968) 473–482. Weisenberg, M., Pain and pain control, Psychol. Bull., 84 (1977) 1008– 1044. Weisenberg, M., Cognitive aspects of pain. In: P.D. Wall and R. Melzack (Eds.), Textbook of Pain, 3rd edn., Churchill Livingstone, Edinburgh, 1994, pp. 275–289. Weisenberg, M., Wolf, Y., Mittwoch, T., Mikulincer, M. and Aviram, O., Subject versus experimenter control in the reaction to pain, Pain, 23 (1985) 187–200. Weisenberg, M., Schwarzwald, J. and Tepper, I., The influence of warning signal and cognitive preparation on the aversiveness of cold-pressor pain, Pain, 64 (1996a) 379–385. Weisenberg, M., Tepper, I. and Schwarzwald, J., Humor as a cognitive technique for increasing pain tolerance, Pain, 63 (1996b) 207–212. Weisz, H., The Influence of Cognitive Preparation, Perceived Self-efficacy, Warning Signal Timing and Recovery Time, on the Aversiveness of Cold-pressor Pain, M.A. thesis, Bar-Ilan University, Ramat-Gan, Israel, 1997, 95 pp. Zelman, D.C., Howland, E.W., Nichols, S.N. and Cleeland, C.S., The effects of induced mood on laboratory pain, Pain, 46 (1991) 105– 111. Ziv, A., The Psychology of Humor, Yahdav Press, Tel-Aviv, Israel, 1981, 247 pp. Zuckerman, M. and Lubin, B., Manual for the Multiple Affect Adjective Checklist, Educational and Industrial Testing Service, San Diego, CA, 1965.