Psychosocial and psychophysical assessments of patients with unexplained chest pain

Psychosocial and Psychophysical Assessments of Patients With Unexplained Chest Pain A.

LAURENCE CATHY

A.

BRADLEY,

SCHAN,

PA-C,

Ph.D., JOEL E. RICHTER,M.D., ISABEL C. SCARINCI,B.S., JULIE M. HAILE, B.A., flirmingham, Alabama

It is imperative to assess the psychosocial factors that may influence the subjective experiences and pain behavior of persons with chronic unexplained chest pain. Both psychologists and physicians tend to rely on self-report measures of psychological distress, which provide little unique information about patients with chronic chest pain to differentiate them from patients with other painful disorders such as irritable bowel syndrome, gastroesophageal reflux disease, or coronary artery disease. However, assessment of pain-coping strategies, spouse responses to the patient’s pain behaviors, and pain thresholds for esophageal balloon distention do differentiate patients with chronic chest pain from healthy controls and patients with various other chronic pain disorders. Specifically, chronic chest pain patients tend to use relatively passive pain-coping strategies such as praying and hoping, and to report relatively high levels of spouse reinforcement of pain behaviors. Finally, in response to esophageal balloon distention, chronic chest pain patients display low pain thresholds that do not generalize to stimulation by mechanical finger pressure. Preliminary evidence suggests these low thresholds are due primarily to a tendency to set low standards for making pain judgments regarding esophageal stimuli of moderate-to-high intensity levels.

From the Drvision of Gastroenterology, University of Alabama at Birmingham, Birmingham, Alabama. Preparation of this article was supported in part by National Institute of Diabetes and Digestive and Kidney Diseases Grant No. ROl DK 42428 to J.E.R. and LAB. Requests for reprints should be addressed to Laurence A. Bradley, Ph.D., Division of Gastroenterology. 633 Zeigler Research Building, University of Alabama at Birmingham, Birmingham, Alabama 35294.

umerous psychosocial factors are associated with increased perception of pain among both chronic pain patients and healthy individuals [1,2; Bradley LA, al, unpublished data, 19911. Studies of patients with unexplained chest pain have focused on only three of these factors. First, experimentally induced stress produces significant increases in the amplitudes of patients’ esophageal peristaltic contractions [3] that generally do not appear to cause episodes of chest pain [4]. Second, chest pain patients with abnormal esophageal motility patterns are characterized by a high prevalence of psychiatric disturbances such as depression and panic disorder [5-81 and by high scores on psychometric measures of anxiety [9]. Finally, chest pain patients with psychiatric disorders tend to use passive strategies (e.g., avoidance and wishful thinking) for coping with their pain, whereas chest pain patients without psychiatric disturbance are more likely to use active strategies, such asseeking social support and other problem-focused coping efforts [ 101. Psychophysical studies have demonstratecl that chest pain patients respond to esophageal balloon distention at significantly lower pain thresholds than do healthy inclivicluals [11,12]. The previously mentioned psychosocial factors have been suggested to account in part for the low pain thresholds ancl high clinical pain levels found in chest pain patients [13,14]. To test this hypothesis, we currently are conducting a prospective case-control study of pain thresholds and psychosocial factors among chest pain patients and four groups of control subjects. The control groups consist of healthy individuals and patients with gastroesophageal reflux disease (GERD), irritable bowel syndrome (IBS), or coronary artery clisease (CAD). These four control groups may permit us to determine whether there are any pain perception or psychosocial factors that differentiate chest pain patients from healthy individuals and from patients with organic chest pain syndromes that either are life threatening (CAD) or pose no direct threat to life (GERD), or from persons with a functional disorder of the lower gastrointestinal tract (IBS).

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STUDY RATIONALE Our investigation is the first attempt to study pain threshold responses of chest pain patients to both esophageal balloon distention and mechanical finger pressure stimuli in order to determine whether the pain threshold responses of chest pain patients are specific to esophageal distention (balloon distention) or represent a generalized response to other noxious stimuli (finger pressure). Second, our investigation is the first attempt to use sensory decision theory [15] to determine which factors underlie differences in pain threshold levels among chest pain patients and other groups. Sensory decision theory methods assess the accuracy with which subjects differentiate stimuli of relatively high and low intensity levels (i.e., discrimination ability) as well as their tendencies to set either high or low standards for reporting these stimuli as painful (i.e., response bias). Although multiple factors determine discrimination ability and response bias, the former generally is believed to depend on intact transmission and neurosensory processing of afferent stimuli, whereas the latter is primarily related to various psychological and environmental factors. The results of our sensory decision theory analysis, then, may have important implications for treatment. If chest pain patients, relative to control subjects, display low pain thresholds for esophageal balloon stimuli and poor discrimination ability, it will indicate that the low thresholds are related to dysfunction of the afferent nervous system, or disordered central processing of noxious stimuli; this would provide impetus to continue to examine the efficacy of pharmacologic agents that affect central nervous system function [16]. However, if chest pain patients display relatively low response bias levels, their low pain thresholds may be due to the effect of psychosocial factors on pain perception. It also is possible for patients’ low pain thresholds to be associated with both poor discrimination ability and low response bias. Evidence that chest pain is correlated with low response bias alone or in conjunction with poor discrimination ability would suggest the need for treatment with cognitive and/or behavioral therapies as well as pharmacologic agents [17], an approach already used with a number of chronic pain syndromes [X3]. Finally, in addition to traditional psychosocial measures, such as anxiety, depression, lifetime psychiatric diagnoses, clinical pain intensity, and pain-coping strategies, our study also assesses patients’ perceptions of self-efficacy for controlling pain and spouse or significant others’ responses to patients’ displays of pain behavior. Self-efficacy refers to the belief that one can perform specific actions that will effectively control one’s pain [I9]. 5A-66S

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Several studies have shown that low levels of selfefficacy are associated with relatively high pain levels [19,20]. Spouse responses also have been shown to be related to patients’ displays of pain behavior such as guarded movement [21]. For example, solicitous responses such as offering assistance tend to reinforce pain behaviors and thus increase the frequency with which they are displayed [21,221. Behavioral therapies that decrease reinforcement of pain behavior and increase reinforcement of healthy behavior (e.g., physical activity, social interaction) produce substantial improvements in function among patients with chronic pain [231. Evidence that chest pain patients, relative to patients with other gastrointestinal disorders or CAD, report low levels of self-efficacy or frequent reinforcements of pain behavior would indicate that cognitive-behavioral interventions should be included in the treatment of chest pain. Our stucly tests several hypotheses. First, with regard to pain perception, it is hypothesized that only chest pain patienk (and not patients with GERD, IBS, or CAD) will show significantly lower pain thresholds than healthy control subjects to esophageal balloon distention, and that these low pain threshold levels will be associated with relatively high levels of clinical pain and with relatively poor discrimination ability and low response bias. In contrast, for mechanical finger pressure, no group differences are expected with regard to pain thresholds or sensory decision theory parameters. With respect to psychosocial factors, it is hypothesized that both chest pain and IBS patients will show significantly higher levels of anxiety and depression and a greater number of lifetime psychiatric diagnoses than healthy controls and patients with organic chest pain syndromes (i.e., CAD and GERD). No differences are expected between the chest pain and IBS patients, based on the results of previous studies [63. It also is anticipated that chest pain and IBS patients will report significantly greater use of negative coping strategies, more frequent solicitous responses from spouses or significant others to pain behavior, and lower perceptions of self-efficacy than patients with either GERD or CAD.

METHODS Subjects To date, we have recruited 24 consecutive chest pain patients (6 male, 18 female), 15 consecutive IBS patients (3 male, 12 female), 32 consecutive GERD patients (16 male, 16 female), and 12 consecutive patients with CAD (8 male, 4 female). We also have recruited 21 healthy control individuals (9 male, 12 female) from among both hospital person-

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TABLE I Inclusion and Exclusion Criteria for Subject Groups Criteria

Group Healthy control

Males and females aged 18-75; no history of chest pain, CAD, I& psychiatric treatment, drug or alcohol abuse, or chronic disabling medical conditions

Unexplained

Males and females aged 18-75 with substernal chest pain 24 times/week for >6 months: (a) angfographic evidence of normal or nonobstructive (~50% luminal diameter narrowing) coronary arteries (subjecl age 240) or(b) normal exercise stress test, normal echocardiogram, and cardiologist evaluation that symptoms are not cardiac in ongrn (subject age ~40); no mrtral valve prolapse; GERD ruled out by endoscopy. 24.hour pH monitoring. or X-ray studies

chest pain

Irritable bowel syndrome

Males and females aged 18-75 with abdominal pain generally relieved by bowel movements, occurs ~6 times/year, and persists ~3 weeks per occurrence; symptoms characterized by at least two of the Manning criteria 1441; organic gastrointestinal disease ruled out by flexible sigmoidoscopy, barium enema, CBC, blood chemistries, and trial of lactose-free diet; no history of CAD

Gastroesophageal

Males and females aged 18-75 with symptoms of heartburn or chest pain ~4 times/week; endoscopic 24.hour pH monitoring evaluation; no history of CAD

reflux disease

Coronary artery disease CAD = coronary

evrdence of esophagitis or posibve

Males and females aged 18-75 with positive coronary angiography (>50% lumrnal diameter narrowing); symptomatic angina 24 times/week; no history of myocardial infarction; no symptoms of significant esophageal disease (e.g., dysphagia, heartburn >2 times/month)

artery disease; GERD = gastroesophageal

reflux disease;

IDS = irritable

bowel syndrome.

Mean (+SEM) Demographic Information by Subject Group

I

GERD Variable

Age (years)* Education (yearsIt Pam duration (months)+ I

(n = 32)

CAD (n = 12)

42.912 2.36 12.66? 0.62 8.27? 1.59

65.17z 3.48 14.172 0.70 3.262 0.94

(n zp*4)

43.572 3.37 14.05 5 0.53

47.29+ 3.35 I 1.58+ 0.64 3.78+ 0.93

CP = unexplamed chest pam: HC = healthy controls; F = F test; other abbreviations l Fl4,99) = 6.43; CAD > IBS. CP, HC, GERD. p = 0.0001. W(4.99) = 3.44; 19s >‘ CP, p = 0.01. tF(3.76) = 2.66; p = 0.05.

43.072 3.28 14.40+ 0.71 8.17? 2.23

as in Table I.

nel and the community. The majority of subjects across all samples are Caucasian (83%) and married (62%). There are no significant differences among the subject samples with regard to gender, ethnic background, or marital status. Table I shows the inclusion and exclusion criteria for each sample. Table II shows the mean ages and educational levels of each subject sample and the mean pain durations reported by each. One-way analyses of variance revealed significant differences (p 5 0.05) among the subject samples on each of the three variables. Comparisons using Tukey’s test showecl that the CAD patients are significantly older than those in all other subject groups and that the IBS patients report significantly more years of eclucation than the chest pain patients. There are no significant differences in pain duration between any pair of patient groups. Materials SELF-REPORT INVENTORIES: One self-report measure is administered to all subjects. The Millon Behavioral Health Inventory [24] is a 150-item measure designed specifically to aid in the psychological understanding of medical patients. It consists of 20 scales, each of which has been shown to

May 27,

be reliable and valid [24]. We have chosen to examine only four scales reflecting anxiety (Chronic Tension, Somatic Anxiety), depression (Premorbid Pessimism), and a tendency to show gastrointestinal symptoms in response to stress (Gastrointestinal Susceptibility). These scales allow us to examine psychological traits that may influence pain perception [25]. Three self-report questionnaires are administered to the patient samples but not to healthy controls. The McGill Pain Questionnaire [26] is a reliable, well-valiclatecl verbal descriptor measure of the sensory, emotional, and intensity dimensions of pain. Since there is evidence of high correlations among these dimensions [Holroyd KA, et al, unpublished data, 19911, we have combined them to produce a total pain rating score for analysis. The Coping Strategies Questionnaire [27] is a 50item instrument that provides reliable and valid measures of seven strategies for coping with chronic pain (diverting attention, reinterpreting pain sensations, ignoring pain sensations, coping self-statements, praying or hoping, catastrophizing, and increasing activity level). Praying or hoping and catastrophizing appear to be especially maladaptive strategies because they are associated 1992

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with high levels of pain and disability. There also are two other scales that may be combined to evaluate subjects’ beliefs regarding their self-efficacy, i.e., ability to use their coping strategies .to control their pain. Identification of maladaptive coping strategies commonly used by chest pain patients may provide specific targets, in addition to perceptions of low self-efficacy, for cognitive-behavioral interventions. Part 2 of the Multidimensional Pain Inventory [28] is a reliable and valid measure of spouses’ or significant others’ responses to patients’ displays of pain and suffering. Subjects rate the extent to which each of 14 responses is shown by their spouse or significant other. The 14 items have been categorized in one of three dimensions, i.e., solicitous (“Gives me pain medication”), distracting (“Involves me in activities”), and punishing (“Expresses anger at me”). STRUCTURED PSYCHIATRIC INTERVIEW: Allsubjects are administered the Diagnostic Interview Schedule (DIS) III-A [29]. The DIS is a highly structured interview designed to derive reliable and valid psychiatric diagnoses, based on the Diagnostic and Statistical Manual of Mental DisordersIII (DSM-III) [30]. The DIS was chosen because it may provide information regarding psychological disorders that cannot be derived from self-report inventories. For example, several studies have indicated that panic disorder is diagnosed significantly more often in chest pain patients than in CAD patients [31]. Thus, it has been suggested that effective treatment of panic disorder may reduce the pain and disability of chest pain patients with this diagnosis [32]. Use of the DIS will allow us to determine if panic disorder is diagnosed frequently only in chest pain patients or if it is found often in patients with painful gastrointestinal disorders. INTRAESOPHAGEAL BALLOON: A polyvinyl balloon (length, 30 mm; diameter, 2.5 mm), attached to a standard manometric catheter with silicone glue and 5.0 nylon suture, is used to evaluate subjects’ pain threshold levels to esophageal distention as well as the sensory decision theory parameters of discrimination ability and response bias. This form of noxious stimulation produces unpleasant sensory perceptions that closely resemble chest pain patients’ clinical pain. The catheter is passed through the nose into the stomach and positioned so that the balloon is 10 cm above the lower esophageal sphincter. The balloon is distended with air by the experimenter, who is seated behind the subject using a hand-held syringe with a three-way stopcock, in order to eliminate all visual or auditory cues regarding the volume of each balloon distention. STRAIN GAUGE PAIN STIMULATOR: A strain 5A-68s

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gauge pain stimulator developed by Forgione and Barber has been used to evaluate subjects’ pain threshold levels to mechanical finger pressure, as well as the sensory decision theory parameters [33]. This apparatus consists of a dull lucite knife edge (G mm wide x 0.25 mm thick at point of contact) attached to a lever that can be applied at continuous pressure levels to the second phalanx of any finger. The intensity of pressure stimulation is altered by the magnitudes of a series of weights that may be attached to the lever. These weights are identical in size, shape, color, and all other extraneous cues so that subjects cannot visually discriminate among the weights across trials. This form of noxious stimulation produces dull, aching sensory perceptions that resemble clinical pain unrelated to gastrointestinal disorders. Procedures

All experimental procedures are performed in a single day following an overnight fast and 48-hour abstention from the use of psychotropic and gut motility-altering drugs. The morning is devoted to the assessment of pain threshold levels and sensory decision theory parameters for esophageal balloon distention and mechanical finger pressure. The order of the balloon distention and mechanical stimulation studies is determined randomly for each subject by a coin toss. These studies are separated by a 30-minute rest period. Patients with CAD do not participate in the pain threshold and sensory decision theory parameter assessments because of the potential for experimentally induced pain to provoke a cardiac event. Following completion of the pain threshold and sensory decision theory tasks, subjects are given 1 hour for lunch. They then return to the laboratory and are administered the DIS and self-report measures. ESOPHAGEAL BALLOON DISTENTION: All subjects are studied in a sitting position in a comfortable armchair. Pain threshold is assessed first using a double random staircase procedure that involves the presentation of two “staircases” or series of balloon distention stimuli. Each staircase begins with a 0 mL stimulus and ascends by 1 mL increments to a maximum stimulus of 20 mL. Only one staircase is used for each stimulus trial; the choice of staircase is based on a predetermined, computer-generated random order. The beginning of each trial is signaled by a single auditory tone. The experimenter inflates the esophageal balloon with the appropriate volume of air for 7 seconds. Subjects then are signaled by a double auditory tone to rate the intensity of the stimulus on a 7-point scale (0 = no sensation, 1 = slight sensation, 2 = moderate sensation, 3 = severe sensa-

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Pain Threshold and Sensory Decision Theory Parameters for Esophageal Balloon Distention by Subject Group

Variable Threshold(ml)* Responsebias [mL)t Discriminationerror (%) Means are adjusted for differences m education l F(5,86) = 1.70; CP < GERD. p = 0.08. tF(5,86) = 2.00; CP < HC, p = 0.05.

CP

IBS

GERD

II.00 + 0.98 9.29-c0.19 28.75+ 1.27

12.33r 1.23 9.81t 0.24 26.87t 1.59

13.46+ 0.83 9.69+ 0.16 29.20f 1.07

HC

11.62+ 1.04 9.98-i 0.20 27.80? 1.34 and age. Abbrevtatlons

as in Tables I and II.

tion, 4 = slight pain, 5 = moderate pain, G = jects’ pain threshold levels are first determined using the same clouble random staircase procedure severe pain). -This rating is then used to determine employed with balloon distention. However, each the intensity of the next stimulus presentation from staircase of pressure stimuli begins with a 30 g the same staircase. If a stimulus is judged not painful, the intensity of the next stimulus presented stimulus applied to a finger for 7 seconds and asfrom that staircase is increased by 1 mL. Con- cends by 5 g increments to a maximum stimulus of versely, if a stimulus is rated as painful, the inten155 g. The four fingers of each hand are used during sity of the next stimulus presented from that stairthe pain threshold assessment; the particular finger case is decreased by 1 mL. The random changes and choice of staircase used for each trial are based from one staircase to another prevent subjects from on a predetermined random order. Pain threshold perceiving a reliable relationship between their re- is calculated as the mean weight of the first three sponses and subsequent levels of stimulus intensity pressure stimuli on each staircase that have been [14]. The stimulus trial ends when the balloon is rated as 24. deflated for a lo-second rest period after the subFollowing a 5-minute rest, 12 practice trials and jects make their intensity rating. The pain threshthe sensory decision theory task are administered old assessment is terminated when three stimuli using four stimuli (40 g, 70 g, 85 g, and 115 g). Finfrom each staircase have been rated as r4 (“slight gers are stimulated in the following order: right pain”). Pain threshold is calculated as the mean vol- index finger, left index finger, right middle finger, ume of the first three balloon distention stimuli on left micldle finger, right ring finger, left ring finger, each staircase that have been rated as 24. right little finger, left little finger. All other aspects Following a 5-minute rest, a practice sensory of the practice trials and sensory decision theory decision theory task is administered to subjects (12 task, including the calculation of the nonparametric practice stimulation trials consisting of three trials indexes of discrimination ability and response bias, at each of four stimulus intensities [12 mL, 8 mL, 7 are identical to those used with esophageal balloon mL, 3 mL]). The practice trial procedure is identidistention. cal to that used for pain threshold assessment except that the stimuli are presented in a predeterStatistical Analyses mined random order with the stipulation that every Every dependent variable was entered in a onefour-trial block contains each of the intensities. way analysis of covariance with the betweenAfter another 5-minute rest, the actual sensory subject factor of subject group, Analyses of data decision theory task is administered. This task con- from healthy controls and patient samples were sists of 72 stimulus trials in which each of the four performed with age and education as covariates. stimuli used for practice are presented 18 times, The analyses of data collected only from the patient using the same procedure employed during the samples used age, education, and pain duration as practice trials. To reduce subject fatigue, we in- covariates. Bonferroni t-tests were used to test all clude a 3-minute rest period after the 24th and 48th hypotheses to minimize type 1 (i.e., false-positive) trials. error. Posttest comparisons were performed using Nonparametric sensory decision theory indexes Tukey’s test [36]. of discrimination ability and response bias for each RESULTS subject are calculated using the method suggested by Buchsbaum et al [34]. We use nonparametric Pain Thresholds and Sensory Decision Theory indexes because subjects may not produce normally Parameters distributed responses when ~50 trials per stimulus Table III shows the results of the pain threshold intensity are administered [35]. and sensory decision theory parameter assessMECHANICAL STIMULATION OF THE FINGERS: All ments for esophageal balloon distention. Chest pain subjects sit at a table facing the experimenter. Sub- subjects tended to display lower pain thresholds for May 27,

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IV

Mean

(+SEM)

Pain

and Pain Coping Responses by Subject Group

Variable

CP

IBS

McGill Pain Questionnaire* CSQ praying and hopingt CSQpain control efficacy*

27.18 t 2.51

18.37 + 3.16

Means are l F(6,73) = tF(6,73) = sF(6.73) =

GERD il.02

2.44f 0.41 2.30+ 0.36

3.67? 0.32 2.44f 0.28

adjusted for differences in education and age, and pain duration. 3.59; CP > IBS. GERD. CAD, p cO.02. 3.45; CP > IBS. CAD, p = 0.02. 5.07; CP, IBS < GERD, CAD, p = 0.003.

CSQ = Coping Strategies

CAD

f 2.16

2.912 0.28 3.45t 0.24 Questionnaire;

other abbwations

16.912 4.34 2.45? 0.56 3.51f 0.49

as in Tables I and Il.

TABLE V Mean (+SEM) Number of Psychiatric Diagnoses (DSM-III) by Subject Group Variable

HC

CP

IBS

GERD

Number of dragnoses*

1.57 f 0.51

2.32c 0.48

3.35f 0.61

3.21? 0.41

,

cleans are adjusted for differences in education ‘F(6.97) = 3.84; GERD, I8S > HC. p = 0.006.

and age. Abbrewations

Clinical Pain Intensity, Coping Strategies, and Self-Efficacy

Table IV shows the subject groups’ mean responses to the McGill Pain Questionnaire and two Coping Strategies Questionnaire (CSQ) scales. There was a significant main effect of subject group on the McGill Pain Questionnaire (p < 0.02); chest pain subjects reported significantly higher clinical pain ratings than did all other subject groups (p I 0.05). There also was a significant main effect of subject group on the CSQ (p = 0.02); chest pain subjects tended to report greater use of praying and hoping strategies than all of the other patient samples. Furthermore, chest pain subjects’ use of praying and hoping was significantly greater than that reported by both IBS and CAD subjects (p 5 0.05). Finally, there was a significant main effect of subject group on the CSQ self-efficacy measure May 27,

1.942 0.75

as in Tables I and II.

balloon distention than all other subject groups (p = 0.08) and hacl significantly lower thresholds (p < 0.05) than GERD subjects. There also was a significant tendency for chest pain subjects to produce lower response bias parameters for balloon distention than subjects in all other groups (p < 0.05). Consistent with our hypothesis, there was a significant (1) < 0.05) difference in response bias between the chest pain and healthy control subjects, indicating that chest pain subjects used a lower standard than did healthy controls for judging esophageal balloon distention stimuli as painful. There were no between-group clifferences regarding discrimination ability for these stimuli. Similarly, no differences were founcl with regard to pain threshold levels or sensory decision theory parameters for mechanical finger pressure stimuli.

%I-70s

CAD

(p = 0.003); the chest pain ancl IBS subjects reported significantly lower levels of efficacy for controlling their pain than did GERD and CAD subjects (p I 0.05).

Psychiatric Diagnosesand Psychological Distress

Table V shows the mean number of lifetime psychiatric diagnoses identified by the DIS within each subject group. There was a significant main effect of subject group (p = 0.006); the GERD and IBS groups had significantly greater numbers of psychiatric diagnoses than the healthy control sample (p < 0.03). Examination of indiviclual psychiatric diagnoses revealecl that a significant difference among the subject groups occurred only for dysthymic disorder (p = 0.03). This clisorder is characterized by periods of depressed mood that are not of sufficient duration or severity to meet the DSM-III criteria for major depressive episode. Whereas 2540% of GERD, chest pain, and IBS patients received a diagnosis of dysthymic disorder, only 10% of the healthy control sample and no CAD subjects receivecl this cliagnosis. In contrast to the results of previous studies [33], no difference was found among the subject groups in diagnosis of panic disorder. Table VI shows subjects’ mean scores on the four Millon Behavioral Health Inventory measures of psychological distress. Significant main effects of subject group were found on the Premorbid Pessimism (p < O.OOl), Somatic Anxiety (p = 0.007), and Gastrointestinal Susceptibility (p = 0.0001) scales. Both GERD and IBS subjects produced significantly higher Premorbid Pessimism scores than healthy controls (p < 0.05). In addition, all patient

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TABLE VI Mean (+SEM) Millon Behavioral Health Inventory Scores by Subject Group

1

Variable

HC

CP

IBS

GERD

CAD

Chronic tension Premorbid pessimism* Somaticanxietyt Gastrointestinalsusceptibility#

48.21 + 5.91 40.17 + 5.48

48.402 5.63

36.53f 5.04 48.342 4.01

50.69? 4.80 66.04? 3.82

46.58+ 7.01 60.91? 6.51 53.052 5.98 67.25t 4.76

58.13+_4.81 61.45+ 4.47 58.05+ 4.10 69.07+ 3.27

55.392 8.68 46.582 8.06 57.98+ 7.40 64.722 5.89

Means *F(6.97) tF(6,97) @(6,97)

are = = =

adjusted for differences in education and age. Abbreviations 4.53; GERD. IDS > HC. p < 0.001. 3.71; CP, 18s. GERD, CAD > HC, p = 0.007. 6.29; CP, IBS. GERD, CAD > HC, p = 0.0001.

54.14 + 5.23

as in Table I and II.

TABLE VII Mean (&EM)

Ratings of Spouse or Significant Other Response to Pain by Subject Group

Variable

CP

IBS

GERD

CAD

Punishing Solicitous* Oistractingt

0.69 f 0.34

1.46 + 0.49

3.982 0.36 2.25t 0.27

2.02+ 0.51 0.81+ 0.39

1.542 0.31 3.812 0.33 1.85+ 0.25

0.55f 0.57 3.38+ 0.60 1.38+ 0.45

Means are adjusted for differences in age, education, *F(6.58) = 3.94; CP, GERD > IRS. p < 0.02. tF(6,58) = 3.47; CP, GERD > IES. p = 0.02.

and pain duration;

subjects without close relationships

samples produced significantly higher Somatic Anxiety and Gastrointestinal Susceptibility scores than did healthy controls (p < 0.05). Responses to Patients’ Pain and Suffering Table VII shows subjects’ mean Multidimensional Pain Inventory ratings of their spouses’ or significant others’ responses to their pain behavior. There were significant main effects of subject group on the Solicitous and Distracting scales (p 5 0.02). Between-group comparisons showed that, relative to IBS subjects, both chest pain and GERD subjects reported that they more frequently receive solicitous and distracting responses (p < 0.02). COMMENT The results of this preliminary examination of an ongoing investigation suggest that several pain perception and psychosocial factors differentiate chest pain patients from patients with GERD, IBS, or CAD as well as from healthy individuals. Response Bias and Sensory Decision Theory Parameters We found strong tendencies for chest pain patients to display the lowest pain threshold and response bias levels for esophageal balloon distention compared with the other patient samples and healthy controls. Due to the small sizes of our samples, however, chest pain patients’ pain threshold and response bias levels differed significantly only

could not be included

in analyses.

Abbreviations

as in Tables l and

from those of GERD patients and healthy controls, respectively. In accord with the pain threshold and sensory decision theory findings, chest pain patients reported significantly higher levels of clinical pain on the McGill Pain Questionnaire than all other patient samples. No significant differences among the subject groups were found on the pain threshold or sensory decision theory parameters for mechanical finger pressure, strongly suggesting that altered pain perception among chest pain patients is specific to visceral stimuli. It is not known whether chest pain patients show low pain thresholds in response to noxious stimuli from other portions of the gastrointestinal tract. It is noteworthy, however, that our IBS patients did not produce lower thresholds for esophageal balloon distention despite the fact that they display lower pain thresholds for rectal balloon distention than healthy controls [37]. These results are consistent with our previous findings of relatively low pain threshold levels among chest pain patients in response to esophageal balloon distention [11,12]. They must be considered tentative and conservative, however, since adequate statistical power will not be achieved until approximately 40 subjects within each sample are tested. Nevertheless, the results suggest that chest pain patients’ low pain thresholds are related primarily to the criteria (response bias) they employ for judging esophageal stimuli as painful. Thus, treatments should include cognitive and/or behavioral interventions that attend to the psycho-

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social dimensions of chest pain. Klimes et al [171 .reeently demonstrated that, relative to a waitinglist control condition, chest pain treatment consisting of education and training in relaxation, slowpaced breathing, and adaptive coping strategies (including exercise) produced significant reductions in pain, clisability, ancl psychological distress that were maintained at a 3-month follow-up assessment. These results are superior to the modest effects on pain that have been produced by pharmacologic agents such as trazoclone [lG] ancl nifeclipine [381

ment of pain behavior and to reward healthy behavior has reduced pain behavior ancl increased functional ability among chronic pain patients [231. Our results also suggest that physicians involved in managing chest pain .patients should beware of inadvertently reinforcing pain behavior. For example, providing meclication on an as-needed basis or instructions to terminate exercise in response to pain produce high levels of disability among persons with acute back pain [42]. Similar reinforcing behaviors shown by chest pain patients’ physicians also may lead to high levels of pain behavior or prolonged disability. Subjects’ responses to the DIS ancl the Millon Psychosocial Factors Our findings suggest that two sets of psychoso- Behavioral Health Inventory produced two unexpected results. We anticipated that the chest pain cial factors that distinguished chest pain patients from those with GERD, IBS, or CAD may be of ancl IBS patients would receive the greatest numparticular importance to treatment. The first was ber of lifetime psychiatric diagnoses ancl would produce the highest scores on the Millon Behavioral patients’ use of pain-coping strategies and perceptions of self-efficacy. The chest pain patients re- Health Inventory measures of psychological clistress. However, we founcl that the GERD and IBS ported significantly greater use of malaclaptive strategies (praying ancl hoping) than did patients samples received the greatest number of lifetime with IBS or CAD. Chest pain patients also re- psychiatric diagnoses. Indeed, the only psychiatric ported significantly lower levels of efficacy for con- diagnosis that was assigned primarily to chest pain trolling their pain than clicl GERD and CAD pa- and IBS patients was clysthymic disorder. We also tients. The belief that one cannot effectively act to found that all patient groups produced significantly control pain may have preclisposed chest pain pa- higher scores than the healthy controls on the SoSusceptibility tients to set lower stanclards for evaluating the matic Anxiety and Gastrointestinal esophageal distention stimuli that resembled their scales. These results may have important implicaclinical symptoms. Future treatment outcome stucl- tions for understanding chest pain patients. First, ies of chest pain should examine the effects of cogni- they indicate that, although psychiatric disorders tive-behavioral interventions that target patients’ and psychological clistress may be associated with use of coping strategies ancl perceptions of self- the pain experiences of some chest pain patients efficacy because these interventions have signifi(e.g., those with motility abnormalities [5]), chest cantly recluced pain and distress among patients pain shoulcl not be considered an artifact of psychiwith osteoarthritis [39] ancl rheumatoid arthritis atric illiiess or distress. Second, our failure to repli[40,41]. cate previous findings [33] of a high prevalence of The seconcl set of distinguishing psychosocial fac- panic disorder among chest pain patients raises tors was the responses of the chest pain patients’ questions about the importance of this disorder for spouses or significant others to displays of pain ancl alterecl pain perception in chest pain. However, the suffering. The chest pain patients reported more DSM-III criteria for panic clisorcler used in our . frequent solicitous and distracting responses than study are substantially more conservative than the clid IBS or CAD patients. As noted, solicitous re- DSM-III-R criteria [43] used in many other investisponses reinforce and elicit high levels of verbal and gations. Thus, we might have identifiecl panic clismotor pain behavior from chronic pain patients order more frequently in chest pain patients had we [21,22]. Distracting responses may reinforce pain usecl the DSM-III-R criteria. Whether chest pain behavior because they represent nurturant behav- patients differ from IBS ancl GERD patients using iors that are produced primarily when patients are DSM-III-R diagnoses of panic clisorcler has not observed to suffer. Reinforcement of pain behavior, been determined. If no differences are found in futhen, may also predispose chest pain patients to set ture studies, it will not be possible to view panic lower standards for judging esophageal stimuli as disorder as a causal factor in chest pain patients’ painful and to report high levels of clinical pain. altered pain perceptions. Thus, 0~1’ results suggest that treatment of chest SUMMARY pain patients might require spouse or significant other training to help reduce the high levels of disOur results indicate that chest pain patients tend ability shown by these patients. Training spouses to differ from patients with other gastrointestinal and other family members to withdraw reinforceclisorders, as well as from healthy persons, in the 5A-72s

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standards they use to judge esophageal distention stimuli as painful. The chest pain patients also differ from the other patient groups with regard to their use of coping strategies, perceptions of selfeffkacy in controlling their pain, and reinforcements of pain behavior by spouses or significant others. This article represents a preliminary examination of an ongoing study. We expect that more substantial differences among our subject samples will emerge after data collection is completecl. Nevertheless, the results suggest that assessments of pain perception and psychosocial variables together will allow us to understand better the factors that contribute to the suffering of persons with chest pain. Ultimately, we believe that this unclerstancling will allow us to develop reliable and effective treatments for chest pain that may include both pharmacologic and cognitive-behavioral components.

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