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Cognitive-behavior therapy for depression: The effects of booster sessions on relapse
BEHAVIORTHERAPY16, 335-344 (1985)
Cognitive,Behavior Therapy for Depression: The Effects of Booster Sessions on Relapse AMANDA L. BAKER PETER H. WILSON
University of Sydney Following seven weekly sessions of group cognitive-behavior therapy, 31 depressed subjects were allocated to either (a) cognitive-behavioralbooster sessions, (b) nonspecific booster sessions, or (c) no booster sessions for a 3-month period. Assessment of depression and related variables occurred prior to the initial treatment, at the end of treatment, and at the end of the booster phase. Depression was also assessed regularly throughout the booster phase. Booster sessions were not effective in reducing relapse or in furthering treatment gains. A high level of depression was reported during the booster/follow-up phase. Initial treatment response was a good predictor of depression level during the follow-up period. There is n o w a fairly large b o d y o f evidence that c o m b i n e d cognitivebehavior therapy is effective in the m a n a g e m e n t o f depression (Blaney, 1981). However, in the studies reported to date, m o s t attention has been paid to the immediate effects o f treatment. Follow-up assessment periods have varied from 4 weeks to 1 year, but the majority have been at the shorter end o f this scale. Most o f these studies reveal that initial treatment effects are m a i n t a i n e d at follow-up. However, it should be noted that such single-point follow-up assessments m a y seriously underestimate the actual relapse rate, as m a n y subjects appear to reach significant levels o f depression during the follow-up period but m a y not be depressed at the single follow-up assessment. Wilson (1982) f o u n d that 28% o f subjects reported clinically significant levels o f depression during a 6 - m o n t h period following various interventions. Kovacs, Rush, Beck, and Hollon (1981) reported that 44% o f subjects reached clinical levels o f depression on the Beck Depression I n v e n t o r y during a 1-year period following cognitiveb e h a v i o r therapy. This study was conducted by the first author under the supervision of the second author in partial fulfillment of the requirements for the degree of Master of Psychology at the University of Sydney. The authors gratefully acknowledge the assistance of Richard O'Kearney in the conduct of initial interviews. Requests for reprints should be sent to Peter H. Wilson, Department of Psychology, Clinical Psychology Unit, University of Sydney, N.S.W. 2006, Australia. 335
0005-7894/85/0335-034451.00/0
Copyright 1985 by Association for Advancement of Behavior Therapy All rights of reproduction in any form reserved.
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An issue related to long-term effects of treatment is the provision of maintenance or "booster" sessions. Kovacs et al. (1981) suggest that "since recurrence of the disorder may be anticipated given the apparent phasic nature of some depressive illnesses, patients at risk could be preselected for maintenance treatments," (p. 38). McLean and Hakstian (1979) also conclude that "the challenge for the future is to find ways to protect clinical improvements by means of effective maintenance programs," (p. 835). The present study was designed to evaluate the efficacy of booster sessions in the prevention of relapse following cognitive-behavioral treatment for depression. Cognitive-behavioral booster sessions were compared with nonspecific booster sessions and a no-booster condition. Regular assessments during the booster treatment period were incorporated in order to evaluate the extent of relapse in each condition. METHOD
Subject Selection Potential subjects were drawn from the general population of Sydney through a media announcement of a depression treatment research program. The Beck Depression Inventory (BDI; Beck, Ward, Mendelson, Mock, & Erbaugh, 1961) and a general history questionnaire were mailed to all respondents. Those respondents who fulfilled the following criteria were invited to attend an initial interview: (a) aged between 20 and 65 years, (b) score of at least 17 on the BDI, (c) frequent periods of depression in the previous 3 months,1 (d) no current psychological or pharmacological treatment (except small doses of minor tranquillizers), and (e) if recently pregnant, at least 6 months postpartum. At the interview stage, further criteria for selection included: (a) score of at least 17 on the BDI upon readministration in the University clinic, (b) fulfillment of the research diagnostic criteria for primary depression (Feighner et al., 1972), (c) fluency in the English language, (d) absence of suicidal ideation, and (e) absence of other psychiatric or physical disorders. Screening questionnaires were mailed to 309 individuals. Replies were received from 205, and interviews were conducted with 74 persons. Forty-two respondents met all screening criteria.
Measures The BDI was employed as the principal measure of depression due to its widespread use and demonstrated psychometric properties (Rehm, 1981). A six-item Significant-Other Rating Scale (Larcombe & Wilson, 1984) was included in order to provide a measure of depression which was relatively independent of subjects' self-reports and less sensitive to the demand characteristics of the testing situation. Self-ratings of best, A report of "frequentperiods of depression in the previous 3 months" was based upon responses to a brief questionnaire dealing with prior experiences of depression that was mailed to subjectsprior to the screeninginterview.
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worst, and average daily mood were made in a manner described elsewhere (Larcombe & Wilson, 1984; Wilson, Goldin, & Charbonneau-Powis, 1983). A 100-item version of the Pleasant Events Schedule (PES) and a 138item Cognition Schedule (which provides retrospective ratings of the frequency of positive and negative thoughts) were included in order to assess changes in treatment-related areas (for further details, see Wilson et al., 1983).
Design Initial treatment phase. Following the pretreatment assessment, 42 subjects, all of whom received the same treatment, were allocated to one of six cognitive-behavior therapy groups. After session two, subject attrition had resulted in one group being reduced in size to include only three participants. Thus, this group was disbanded and the subjects were reallocated to other groups. Six subjects failed to attend the first treatment session. A further five subjects discontinued treatment during the initial treatment phase, leaving 31 subjects who completed the initial treatment phase and attended the posttreatment assessment. Booster treatment phase. Following the initial treatment phase, the remaining subjects were randomly allocated from within each of the five cognitive-behavior therapy groups to one of the three booster conditions. Three subjects discontinued participation in the experiment during the booster phase, resulting in a final distribution of subjects as follows: cognitive-behavioral (n = 10); nonspecific (n = 9), and no-boosters (n -- 9). Administration of all dependent variables was conducted at pretreatment, posttreatment, and at a 4-month follow-up (1 month after the final booster session). Additional administrations of the BDI occurred at each booster session (or the equivalent time for no-booster controls), and at a 5-month follow-up. All subjects received copies of the BDI in the posttreatment session. Subjects in the active booster conditions were sent reminder letters at designated intervals requesting them to return the specified BDI at their next booster session. Subjects in the no-booster condition were sent a reminder requesting them to return the BDI by mail. Therapy Procedures 2 All treatment was conducted by one therapist, a female graduate student in Clinical Psychology. Initial cognitive-behavior therapy. The elements of the treatment were derived from Beck, Rush, Shaw, and Emery (1979) and Lewinsohn, Biglan, and Zeiss (1976). Subjects were treated in groups for weekly 11/2 hr sessions during a 7-week period. Treatment components included (a) activity assignments based on responses to the PES, (b) identification of negative cognitive distortions and irrational beliefs, (c) examination of the validity of negative cognitions, (d) self-recording of events and cog2A moredetaileddescriptionof treatmentproceduresis availablefromthe secondauthor.
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nitions, (e) development and use of positive counterstatements, (f) mood monitoring, and (g) activity monitoring. Behavioral techniques received most attention in the first two sessions, after which the cognitive components were more heavily emphasized. Booster Treatments 3 Subjects received four 11/2hr sessions during a 3-month period in one of two groups per condition. Sessions were held at 2 weeks, and 1, 2, and 3 months following posttreatment. In the cognitive-behavioral condition, the focus was on reviewing and establishing cognitive and behavioral skills to prevent and/or overcome any future depressions. Attention was given to problems which arose between sessions, and strategies were developed for dealing with these difficulties. In the nonspecific condition, the primary focus was on group discussion of problems. The therapist acted as a facilitator, but did not suggest specific cognitive or behavioral strategies. Participants were called upon to offer suggestions and advice to others in the group. Subject Characteristics The final sample consisted of 23 females and 8 males. The mean age was 39.5 years, ranging from 20 to 62 years. Just over half of the subjects were either single, separated, or divorced. Sixty-two percent of the sample reported previous psychiatric or psychological treatment. Statistical Analysis Separate 3 x 3 repeated measures ANOVAs were conducted on each dependent variable. That is, the three booster conditions were factorially combined with the principal assessment occasions. Two orthogonal comparisons were made between treatments: (a) booster sessions vs. no booster sessions, and (b) cognitive-behavioral vs. nonspecific booster sessions. Comparisons between occasions were as follows: (a) pre vs. post, (b) pre vs. follow-up, and (c) post vs. follow-up. In order to avoid inflation of the Type I error rate due to the large number of dependent variables, the Bonferroni correction (Miller, 1966) was applied. A trend analysis was performed on BDI scores obtained during the booster/follow-up phase, involving tests of linear, quadratic, and cubic components of trend (Hays, 1963). The number of subjects who met two different criteria for depression during the booster phase was also examined.
RESULTS The BDI results for all assessment occasions are presented in Table 1. a At least three booster sessions were attended by nine of the ten subjects receiving the cognitive-behavior therapy and all o f the subjects receiving nonspecific booster sessions. Seven cognitive-behavioral, and two nonspecific boosters subjects received one individual session when they were unable to attend group sessions (primarily due to a transport strike).
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TABLE 1 BDI MEANs AND STANDARD DEVIATIONS FOR ALL ASSESSMENT OCCASIONS
Pretreatment Posttreatrnent Booster 1 Booster 2 Booster 3 Booster 4 Follow-up 1 Follow-up 2
M SD M SD M SD M SD M SD M SD M SD M SD
Cognitive behavioral
Nonspecific
No boosters
29.50 4.52 14.10 9.45 15.50 9.15 12.60 8.72 11.90 8.20 11.00 9.22 11.130 11.24 12.10 13.11
25.11 6.65 15.11 9.71 14.89 10.62 13.67 8.25 12.78 8.85 13.22 7.80 13.67 10.34 12.33 7.12
27.00 4.22 19.00 5.56 18.56 5.46 17.67 6.22 17.89 9.17 18.89 10.16 18.22 7.71 17.56 7.38
Pretreatment vs. Posttreatment
T h e r e were significant overall effects for occasions (in the i m p r o v e d direction) on the BDI, F(1, 25) = 44.06, p < .01, Significant-Other Rating Scale, F(1, 20) = 50.09, p < .01, PES Enjoyability, F(1, 25) = 21.55, p < .01, PES Cross-products, F(1, 25) = 18.94, p < .01, Positive Cognition Schedule, F(1, 25) = 29.17, p < .01, a n d Negative Cognition Schedule, F(1, 25) = 22.39, p < .01. T h e effect for occasions a p p r o a c h e d significance o n the PES Frequency, F(1, 25) = 7.34, (Fc = 9.48). N o significant effects for occasions were found on the m o o d ratings. N o n e o f the t r e a t m e n t x occasion interactions were significant ( m o s t Fs were close to 1.00). It should be n o t e d that subjects h a d not actually been allocated to experim e n t a l conditions at this stage. H o w e v e r , the analysis reveals that subjects w h o were eventually allocated to one o f the three booster conditions did not differ in their initial t r e a t m e n t response. Pretreatment vs. Follow-up
Significant effects for occasions (in the i m p r o v e d direction) were found on the BDI, F(1, 25) = 35.53, p < .01, Significant-Other Rating Scale, F(1, 20) = 25.80, p < .01, Positive Cognition Schedule, F(1, 25) = 19.88, p < .01, a n d the N e g a t i v e Cognition Schedule, F(1, 25) = 11.20, p < .05. T h e Booster vs. N o - b o o s t e r x Occasion interactions failed to reach significance on all measures. T h e r e were significant C o g n i t i v e - b e h a v i o r a l Booster vs. Nonspecific Booster x Occasion interactions on the ratings
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o f Best Mood, F(1, 21) = 10.42, p < .05, Worst M o o d , F(1, 21) = 13.36, p < .05, and Average Mood, F(1, 21) = 12.84, p < .05. Examination o f the data revealed that the difference between the booster conditions was probably due to a slight increase in m o o d in the cognitive-behavioral condition in contrast to a slight decrease in the nonspecific condition. The no-booster condition showed no change.
Posttreatment vs. Follow-up There were no main effects for occasions and no significant T r e a t m e n t x Occasion interactions. T h a t is, no significant change occurred from posttreatment to follow-up on any measure and there were no differences between booster conditions in the extent to which i m p r o v e m e n t was maintained.
Trend Analysis There were no significant differences between conditions when averaging across all six testing occasions on the BDI during the booster/followup phase, no significant trend effects, nor any T r e n d x T r e a t m e n t interactions (most Fs < 1). Inspection o f Table 1 reveals that the m e a n BDI scores for each condition remained virtually unchanged throughout the booster/follow-up period.
Proportion of Subjects Reaching Criteria for Depression T w o criteria were adopted for the presence o f depression during the booster/follow-up phase: (a) a BDI score > 17 on any assessment occasion after posttreatment, and (b) a BDI score > 17 on three or m o r e assessment occasions subsequent to posttreatment. The first criterion was met by 6, 4, and 7 subjects in the cognitive-behavioral, nonspecific, and no-booster conditions, respectively (60.7% o f the sample). The second criterion, indicating m o r e chronic difficulties, was met by 4, 3, and 6 subjects in the cognitive-behavioral, nonspecific, and n o - b o o s t e r conditions, respectively (46.4% o f the sample). N o significant differences were found between conditions on either criterion. 4
Relationship Between Response to Initial Treatment and Level of Depression During the Booster/Follow-up Phase T w o 2 x 3 A N O V A s were conducted to examine the effects o f initial treatment response and booster condition on the m e a n level o f depression during the follow-up phase. A BDI score < 13 was used to classify subjects as treatment responders. Mean BDI scores during the follow-up period for experimental conditions according to this criterion o f treatment response are shown in Table 2. The contrast which c o m p a r e d the subsequent course o f depression in responders vs. nonresponders was significant, F(1, 4 These analyses were conducted using both A N O V A and Chi Square tests. The reader is referred to Cochran (1950) and Lunney (1970) for a discussion of the use o f A N O V A with a dichotomous dependent variable.
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TABLE 2 MEAN BDI SCORES DURING BOOSTER/FOLLOW-UP PHASE ACCORDING TO INITIAL TREATMENT RESPONSE Cognitivebehavioral boosters
Nonspecific boosters
No boosters
All conditions
Treatment responders (BDI < 13)
6.75 (n = 4)
7.20 (n = 5)
6.00 (n = 1)
6.90
Treatment nonresponders (BDI => 13)
16.00 (n = 6)
21.25 (n = 4)
19.63 (n = 8)
18.79
22) --- 17.19, p < .01. All other main effects and interactions failed to reach significance. Inspection of BDI means during the follow-up period reveals that nonresponders to initial treatment remained much more depressed than responders. There were no differences between responders and nonresponders on pretreatment BDI scores (responders: M = 26.70; nonresponders: M = 28.17).
DISCUSSION The degree of improvement found in this study is less than that reported in many other studies (cf. Dunn, 1979; McLean & Hakstian, 1979; Rush, Beck, Kovacs, & Hollon, 1977) with similar treatments. However, in recent studies of self-control treatments for depression (Kornblith, Rehm, O'Hara, & Lamparski, 1983; Rehm, Kornblith, O'Hara, Lamparski, Romano, & Volkin, 1981), and in one other study of cognitive therapy (de Jong, Henrich, & Ferstl, 1981), similar pre-post changes have been reported (from 29.2 to 15.3). It is possible that for the severely depressed sample represented in the present study, the group format and relatively brief treatment may have reduced the overall effectiveness of the therapy program. In the absence of waiting list and nonspecific control groups, the processes of natural remission and nonspecific factors cannot be excluded as the causes of improvement during the initial treatment phase. For the sample as a whole, posttreatment effects were maintained during the booster/follow-up phase, but there was no evidence that booster sessions were helpful in the prevention of relapse. Of course, the extent to which booster sessions can be shown to prevent relapse depends partly on the success of the initial intervention in reducing depression. It is possible that two few subjects responded sufficiently well in the first place to demonstrate any effects of booster sessions on relapse. However, one can at least conclude that subjects in the booster conditions made no further gains with the additional intermittent treatment, an interesting finding itself. A major finding of the present study was that those subjects who were classified as good responders to initial treatment remained improved dur-
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ing the booster/follow-up period and that subjects who failed to respond well to treatment continued to be depressed during the booster/followup phase. This differential long-term outcome was not simply a reflection of differences in initial depression level. It should be noted, however, that the allocation of subjects to booster conditions did not take account of individual treatment response. Unfortunately, the random allocation resuited in an unequal distribution of subjects in each experimental condition according to level of improvement, precluding a definitive conclusion regarding the effect of the three booster conditions when taking initial treatment response into account. One tentative conclusion is that regardless of booster sessions or booster type, subjects who improve during treatment remain improved. A large proportion of subjects (46.4-60.7%, depending on the criterion) reported depressive symptoms during the booster/follow-up phase. Unfortunately, there are very few studies of cognitive-behavior therapy against which this result can be compared. Kovacs et al. (1981) report that 44% of their subjects were symptomatic during a one-year follow-up. Kornblith et al. (1983) found that 18 out of 34 subjects (52.9%) experienced at least one episode of depression during a 3-month period following self-control treatments with similar success rates as obtained in the present study. Teasdale, Fennell, Hibbert, and Amies (1984) report that 6 out of 16 subjects (37.5%) obtained a BDI score of >_-14 at a 3-month follow-up. Our criterion for chronic depression produces figures comparable to these studies, while our less stringent criterion is higher than all of these studies, possibly because of the lower initial success rate. Unfortunately, the criteria employed in these studies vary widely, making meaningful comparisons rather difficult. In addition, the figures in these studies probably include a proportion of subjects who did not respond well to treatment in the first place. The results of the present study underscore the need to examine the course of initial treatment responders and nonresponders separately. The mood rating results are inconsistent with previous studies (Larcombe & Wilson, 1984; Wilson et al., 1983), in which ratings of worst mood paralleled the BDI results. It is possible that stronger treatment effects are required before changes on specific symptoms are revealed. However, the follow-up results suggest that these mood ratings may be not as reliable as previously considered. In conclusion, the results provide qualified support for the short- and long-term efficacy of group cognitive-behavioral treatment for depression. Contrary to the frequently expressed recommendation that booster sessions may be an important maintenance strategy, the present findings suggest that this may not be the case. When clinically significant effects are obtained, these effects tend to be maintained. It appears that without good initial treatment response, improvement in the longer term is much less likely to occur. This study is not without its methodological problems, including the small sample size, the use of only one therapist, the heavy reliance on a self-report measure of depression, and the interpretative difficulties caused by the poor initial treatment response. However, the
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results of the present study suggest that attention should be given to understanding the reasons for the variation in treatment response between studies (and between individuals). Most importantly, we urge researchers to report on the subsequent course of depression in subjects identified as responders or nonresponders.
REFERENCES Beck, A. T., Rush, A. J., Shaw, B. F., & Emery, G. (1979). Cognitive therapy of depression. New York: Guilford. Beck, A. T., Ward, C. H., Mendelson, M., Mock, J., & Erbangh, J. (1961). An inventory for measuring depression. Archives of General Psychiatry, 4, 561-571. Blaney, P. H. (1981). The effectiveness of cognitive and behavioral therapies. In L. P. Rehm (Ed.), Behavior therapy for depression: Present status and future directions. New York: Academic Press. Cochran, W.G. (1950). The comparison of percentages in matched samples. Biometrika, 37, 256-266. de Jong, R., Henrich, G., & Ferstl, R. (1981). A behavioural treatment programme for neurotic depression. Behavioural Analysis and Modification, 4, 267-274. Dunn, R. J. (1979). Cognitive modification with depression-prone psychiatric patients. Cognitive Therapy and Research, 3, 307-317. Feighner, J. P., Robins, E., Guze, S. B., Woodruff, R. A., Winokur, G., & Munoz, R. (1972). Diagnostic criteria for use in psychiatric research. Archives of General Psychiatry, 26, 57-63. Hays, W. L. (1963). Statistics for psychologists. New York: Holt, Rinehart & Winston. Kornblith, S. J., Rehm, L. P., O'Hara, M. W., & Lamparski, D.M. (1983). The contribution of self-reinforcement training and behavioral assignments to the efficacy of self-control therapy for depression. Cognitive Therapy and Research, 7, 499-528. Kovacs, M., Rush, A. J,, Beck, A. T., & Hollon, S.D. (198 l). Depressed outpatients treated with cognitive therapy or pharmacotherapy. Archives of General Psychiatry, 38, 33-39. Larcombe, N. A., & Wilson, P. H. (1984). An evaluation ofcognitive-behaviourtherapy for depression in patients with multiple sclerosis. British Journal of Psychiatry, 145, 366-371. Lewinsohn, P. M., Biglan, A., & Zeiss, A.M. (1976). Behavioral treatment of depression. In P. O. Davidson (Ed.), The behavioral management of anxiety, depression and pain. New York: Brunner/Mazel. Lunney, G.H. (1970). Using analysis of variance with a dichotomous dependent variable: An empirical study. Journal of Educational Measurement, 7, 263-269. McLean, P. D., & Hakstian, A. R. (1979). Clinical depression: Comparative efficacy of outpatient treatments. Journal of Consulting and Clinical Psychology, 47, 818-836. Miller, R. G. (1966). Simultaneous statistical inference. New York: McGraw-Hill. Rehm, L. P. (1981). Assessment of depression. In M. Hersen & A. S. Bellack (Eds.), Behavioral assessment: A practical handbook. New York: Pergamon Press. Rehm, L. P.,Kornblith, S. J., O'Hara, M. W., Lamparski, D. M., Romano, J. M., & Volkin, J.I. (1981). An evaluation of major components in a self-control therapy program for depression. Behavior Modification, 5, 459-489. Rush, A. J., Beck, A. T., Kovacs, M., & Hollon, S. (1977). Comparative efficacyof cognitive therapy and pharmacotherapy in the treatment of depressed outpatients. Cognitive Therapy and Research, 1, 17-37. Teasdale, J. D., Fennell, M. J. V., Hihbert, G. A., & Amies, P.L. (1984). Cognitive therapy for major depressive disorder in primary care. British Journal of Psychiatry, 144, 400406.
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Wilson, P.H. (1982). Combined pharmacological and behavioural treatment ofdepression. Behaviour Research and Therapy, 20, 173-184. Wilson, P. H., Goldin, J. C., & Charbonneau-Powis, M. (1983). Comparative efficacy of behavioral and cognitive treatments of depression. Cognitive Therapy and Research, 7, 111-124. RECEIVED"August 9, 1984 FINAL ACCEPTANCE:January 24, 1985
Cognitive,Behavior Therapy for Depression: The Effects of Booster Sessions on Relapse AMANDA L. BAKER PETER H. WILSON
University of Sydney Following seven weekly sessions of group cognitive-behavior therapy, 31 depressed subjects were allocated to either (a) cognitive-behavioralbooster sessions, (b) nonspecific booster sessions, or (c) no booster sessions for a 3-month period. Assessment of depression and related variables occurred prior to the initial treatment, at the end of treatment, and at the end of the booster phase. Depression was also assessed regularly throughout the booster phase. Booster sessions were not effective in reducing relapse or in furthering treatment gains. A high level of depression was reported during the booster/follow-up phase. Initial treatment response was a good predictor of depression level during the follow-up period. There is n o w a fairly large b o d y o f evidence that c o m b i n e d cognitivebehavior therapy is effective in the m a n a g e m e n t o f depression (Blaney, 1981). However, in the studies reported to date, m o s t attention has been paid to the immediate effects o f treatment. Follow-up assessment periods have varied from 4 weeks to 1 year, but the majority have been at the shorter end o f this scale. Most o f these studies reveal that initial treatment effects are m a i n t a i n e d at follow-up. However, it should be noted that such single-point follow-up assessments m a y seriously underestimate the actual relapse rate, as m a n y subjects appear to reach significant levels o f depression during the follow-up period but m a y not be depressed at the single follow-up assessment. Wilson (1982) f o u n d that 28% o f subjects reported clinically significant levels o f depression during a 6 - m o n t h period following various interventions. Kovacs, Rush, Beck, and Hollon (1981) reported that 44% o f subjects reached clinical levels o f depression on the Beck Depression I n v e n t o r y during a 1-year period following cognitiveb e h a v i o r therapy. This study was conducted by the first author under the supervision of the second author in partial fulfillment of the requirements for the degree of Master of Psychology at the University of Sydney. The authors gratefully acknowledge the assistance of Richard O'Kearney in the conduct of initial interviews. Requests for reprints should be sent to Peter H. Wilson, Department of Psychology, Clinical Psychology Unit, University of Sydney, N.S.W. 2006, Australia. 335
0005-7894/85/0335-034451.00/0
Copyright 1985 by Association for Advancement of Behavior Therapy All rights of reproduction in any form reserved.
336
BAKER A N D WILSON
An issue related to long-term effects of treatment is the provision of maintenance or "booster" sessions. Kovacs et al. (1981) suggest that "since recurrence of the disorder may be anticipated given the apparent phasic nature of some depressive illnesses, patients at risk could be preselected for maintenance treatments," (p. 38). McLean and Hakstian (1979) also conclude that "the challenge for the future is to find ways to protect clinical improvements by means of effective maintenance programs," (p. 835). The present study was designed to evaluate the efficacy of booster sessions in the prevention of relapse following cognitive-behavioral treatment for depression. Cognitive-behavioral booster sessions were compared with nonspecific booster sessions and a no-booster condition. Regular assessments during the booster treatment period were incorporated in order to evaluate the extent of relapse in each condition. METHOD
Subject Selection Potential subjects were drawn from the general population of Sydney through a media announcement of a depression treatment research program. The Beck Depression Inventory (BDI; Beck, Ward, Mendelson, Mock, & Erbaugh, 1961) and a general history questionnaire were mailed to all respondents. Those respondents who fulfilled the following criteria were invited to attend an initial interview: (a) aged between 20 and 65 years, (b) score of at least 17 on the BDI, (c) frequent periods of depression in the previous 3 months,1 (d) no current psychological or pharmacological treatment (except small doses of minor tranquillizers), and (e) if recently pregnant, at least 6 months postpartum. At the interview stage, further criteria for selection included: (a) score of at least 17 on the BDI upon readministration in the University clinic, (b) fulfillment of the research diagnostic criteria for primary depression (Feighner et al., 1972), (c) fluency in the English language, (d) absence of suicidal ideation, and (e) absence of other psychiatric or physical disorders. Screening questionnaires were mailed to 309 individuals. Replies were received from 205, and interviews were conducted with 74 persons. Forty-two respondents met all screening criteria.
Measures The BDI was employed as the principal measure of depression due to its widespread use and demonstrated psychometric properties (Rehm, 1981). A six-item Significant-Other Rating Scale (Larcombe & Wilson, 1984) was included in order to provide a measure of depression which was relatively independent of subjects' self-reports and less sensitive to the demand characteristics of the testing situation. Self-ratings of best, A report of "frequentperiods of depression in the previous 3 months" was based upon responses to a brief questionnaire dealing with prior experiences of depression that was mailed to subjectsprior to the screeninginterview.
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337
worst, and average daily mood were made in a manner described elsewhere (Larcombe & Wilson, 1984; Wilson, Goldin, & Charbonneau-Powis, 1983). A 100-item version of the Pleasant Events Schedule (PES) and a 138item Cognition Schedule (which provides retrospective ratings of the frequency of positive and negative thoughts) were included in order to assess changes in treatment-related areas (for further details, see Wilson et al., 1983).
Design Initial treatment phase. Following the pretreatment assessment, 42 subjects, all of whom received the same treatment, were allocated to one of six cognitive-behavior therapy groups. After session two, subject attrition had resulted in one group being reduced in size to include only three participants. Thus, this group was disbanded and the subjects were reallocated to other groups. Six subjects failed to attend the first treatment session. A further five subjects discontinued treatment during the initial treatment phase, leaving 31 subjects who completed the initial treatment phase and attended the posttreatment assessment. Booster treatment phase. Following the initial treatment phase, the remaining subjects were randomly allocated from within each of the five cognitive-behavior therapy groups to one of the three booster conditions. Three subjects discontinued participation in the experiment during the booster phase, resulting in a final distribution of subjects as follows: cognitive-behavioral (n = 10); nonspecific (n = 9), and no-boosters (n -- 9). Administration of all dependent variables was conducted at pretreatment, posttreatment, and at a 4-month follow-up (1 month after the final booster session). Additional administrations of the BDI occurred at each booster session (or the equivalent time for no-booster controls), and at a 5-month follow-up. All subjects received copies of the BDI in the posttreatment session. Subjects in the active booster conditions were sent reminder letters at designated intervals requesting them to return the specified BDI at their next booster session. Subjects in the no-booster condition were sent a reminder requesting them to return the BDI by mail. Therapy Procedures 2 All treatment was conducted by one therapist, a female graduate student in Clinical Psychology. Initial cognitive-behavior therapy. The elements of the treatment were derived from Beck, Rush, Shaw, and Emery (1979) and Lewinsohn, Biglan, and Zeiss (1976). Subjects were treated in groups for weekly 11/2 hr sessions during a 7-week period. Treatment components included (a) activity assignments based on responses to the PES, (b) identification of negative cognitive distortions and irrational beliefs, (c) examination of the validity of negative cognitions, (d) self-recording of events and cog2A moredetaileddescriptionof treatmentproceduresis availablefromthe secondauthor.
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nitions, (e) development and use of positive counterstatements, (f) mood monitoring, and (g) activity monitoring. Behavioral techniques received most attention in the first two sessions, after which the cognitive components were more heavily emphasized. Booster Treatments 3 Subjects received four 11/2hr sessions during a 3-month period in one of two groups per condition. Sessions were held at 2 weeks, and 1, 2, and 3 months following posttreatment. In the cognitive-behavioral condition, the focus was on reviewing and establishing cognitive and behavioral skills to prevent and/or overcome any future depressions. Attention was given to problems which arose between sessions, and strategies were developed for dealing with these difficulties. In the nonspecific condition, the primary focus was on group discussion of problems. The therapist acted as a facilitator, but did not suggest specific cognitive or behavioral strategies. Participants were called upon to offer suggestions and advice to others in the group. Subject Characteristics The final sample consisted of 23 females and 8 males. The mean age was 39.5 years, ranging from 20 to 62 years. Just over half of the subjects were either single, separated, or divorced. Sixty-two percent of the sample reported previous psychiatric or psychological treatment. Statistical Analysis Separate 3 x 3 repeated measures ANOVAs were conducted on each dependent variable. That is, the three booster conditions were factorially combined with the principal assessment occasions. Two orthogonal comparisons were made between treatments: (a) booster sessions vs. no booster sessions, and (b) cognitive-behavioral vs. nonspecific booster sessions. Comparisons between occasions were as follows: (a) pre vs. post, (b) pre vs. follow-up, and (c) post vs. follow-up. In order to avoid inflation of the Type I error rate due to the large number of dependent variables, the Bonferroni correction (Miller, 1966) was applied. A trend analysis was performed on BDI scores obtained during the booster/follow-up phase, involving tests of linear, quadratic, and cubic components of trend (Hays, 1963). The number of subjects who met two different criteria for depression during the booster phase was also examined.
RESULTS The BDI results for all assessment occasions are presented in Table 1. a At least three booster sessions were attended by nine of the ten subjects receiving the cognitive-behavior therapy and all o f the subjects receiving nonspecific booster sessions. Seven cognitive-behavioral, and two nonspecific boosters subjects received one individual session when they were unable to attend group sessions (primarily due to a transport strike).
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TABLE 1 BDI MEANs AND STANDARD DEVIATIONS FOR ALL ASSESSMENT OCCASIONS
Pretreatment Posttreatrnent Booster 1 Booster 2 Booster 3 Booster 4 Follow-up 1 Follow-up 2
M SD M SD M SD M SD M SD M SD M SD M SD
Cognitive behavioral
Nonspecific
No boosters
29.50 4.52 14.10 9.45 15.50 9.15 12.60 8.72 11.90 8.20 11.00 9.22 11.130 11.24 12.10 13.11
25.11 6.65 15.11 9.71 14.89 10.62 13.67 8.25 12.78 8.85 13.22 7.80 13.67 10.34 12.33 7.12
27.00 4.22 19.00 5.56 18.56 5.46 17.67 6.22 17.89 9.17 18.89 10.16 18.22 7.71 17.56 7.38
Pretreatment vs. Posttreatment
T h e r e were significant overall effects for occasions (in the i m p r o v e d direction) on the BDI, F(1, 25) = 44.06, p < .01, Significant-Other Rating Scale, F(1, 20) = 50.09, p < .01, PES Enjoyability, F(1, 25) = 21.55, p < .01, PES Cross-products, F(1, 25) = 18.94, p < .01, Positive Cognition Schedule, F(1, 25) = 29.17, p < .01, a n d Negative Cognition Schedule, F(1, 25) = 22.39, p < .01. T h e effect for occasions a p p r o a c h e d significance o n the PES Frequency, F(1, 25) = 7.34, (Fc = 9.48). N o significant effects for occasions were found on the m o o d ratings. N o n e o f the t r e a t m e n t x occasion interactions were significant ( m o s t Fs were close to 1.00). It should be n o t e d that subjects h a d not actually been allocated to experim e n t a l conditions at this stage. H o w e v e r , the analysis reveals that subjects w h o were eventually allocated to one o f the three booster conditions did not differ in their initial t r e a t m e n t response. Pretreatment vs. Follow-up
Significant effects for occasions (in the i m p r o v e d direction) were found on the BDI, F(1, 25) = 35.53, p < .01, Significant-Other Rating Scale, F(1, 20) = 25.80, p < .01, Positive Cognition Schedule, F(1, 25) = 19.88, p < .01, a n d the N e g a t i v e Cognition Schedule, F(1, 25) = 11.20, p < .05. T h e Booster vs. N o - b o o s t e r x Occasion interactions failed to reach significance on all measures. T h e r e were significant C o g n i t i v e - b e h a v i o r a l Booster vs. Nonspecific Booster x Occasion interactions on the ratings
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o f Best Mood, F(1, 21) = 10.42, p < .05, Worst M o o d , F(1, 21) = 13.36, p < .05, and Average Mood, F(1, 21) = 12.84, p < .05. Examination o f the data revealed that the difference between the booster conditions was probably due to a slight increase in m o o d in the cognitive-behavioral condition in contrast to a slight decrease in the nonspecific condition. The no-booster condition showed no change.
Posttreatment vs. Follow-up There were no main effects for occasions and no significant T r e a t m e n t x Occasion interactions. T h a t is, no significant change occurred from posttreatment to follow-up on any measure and there were no differences between booster conditions in the extent to which i m p r o v e m e n t was maintained.
Trend Analysis There were no significant differences between conditions when averaging across all six testing occasions on the BDI during the booster/followup phase, no significant trend effects, nor any T r e n d x T r e a t m e n t interactions (most Fs < 1). Inspection o f Table 1 reveals that the m e a n BDI scores for each condition remained virtually unchanged throughout the booster/follow-up period.
Proportion of Subjects Reaching Criteria for Depression T w o criteria were adopted for the presence o f depression during the booster/follow-up phase: (a) a BDI score > 17 on any assessment occasion after posttreatment, and (b) a BDI score > 17 on three or m o r e assessment occasions subsequent to posttreatment. The first criterion was met by 6, 4, and 7 subjects in the cognitive-behavioral, nonspecific, and no-booster conditions, respectively (60.7% o f the sample). The second criterion, indicating m o r e chronic difficulties, was met by 4, 3, and 6 subjects in the cognitive-behavioral, nonspecific, and n o - b o o s t e r conditions, respectively (46.4% o f the sample). N o significant differences were found between conditions on either criterion. 4
Relationship Between Response to Initial Treatment and Level of Depression During the Booster/Follow-up Phase T w o 2 x 3 A N O V A s were conducted to examine the effects o f initial treatment response and booster condition on the m e a n level o f depression during the follow-up phase. A BDI score < 13 was used to classify subjects as treatment responders. Mean BDI scores during the follow-up period for experimental conditions according to this criterion o f treatment response are shown in Table 2. The contrast which c o m p a r e d the subsequent course o f depression in responders vs. nonresponders was significant, F(1, 4 These analyses were conducted using both A N O V A and Chi Square tests. The reader is referred to Cochran (1950) and Lunney (1970) for a discussion of the use o f A N O V A with a dichotomous dependent variable.
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TABLE 2 MEAN BDI SCORES DURING BOOSTER/FOLLOW-UP PHASE ACCORDING TO INITIAL TREATMENT RESPONSE Cognitivebehavioral boosters
Nonspecific boosters
No boosters
All conditions
Treatment responders (BDI < 13)
6.75 (n = 4)
7.20 (n = 5)
6.00 (n = 1)
6.90
Treatment nonresponders (BDI => 13)
16.00 (n = 6)
21.25 (n = 4)
19.63 (n = 8)
18.79
22) --- 17.19, p < .01. All other main effects and interactions failed to reach significance. Inspection of BDI means during the follow-up period reveals that nonresponders to initial treatment remained much more depressed than responders. There were no differences between responders and nonresponders on pretreatment BDI scores (responders: M = 26.70; nonresponders: M = 28.17).
DISCUSSION The degree of improvement found in this study is less than that reported in many other studies (cf. Dunn, 1979; McLean & Hakstian, 1979; Rush, Beck, Kovacs, & Hollon, 1977) with similar treatments. However, in recent studies of self-control treatments for depression (Kornblith, Rehm, O'Hara, & Lamparski, 1983; Rehm, Kornblith, O'Hara, Lamparski, Romano, & Volkin, 1981), and in one other study of cognitive therapy (de Jong, Henrich, & Ferstl, 1981), similar pre-post changes have been reported (from 29.2 to 15.3). It is possible that for the severely depressed sample represented in the present study, the group format and relatively brief treatment may have reduced the overall effectiveness of the therapy program. In the absence of waiting list and nonspecific control groups, the processes of natural remission and nonspecific factors cannot be excluded as the causes of improvement during the initial treatment phase. For the sample as a whole, posttreatment effects were maintained during the booster/follow-up phase, but there was no evidence that booster sessions were helpful in the prevention of relapse. Of course, the extent to which booster sessions can be shown to prevent relapse depends partly on the success of the initial intervention in reducing depression. It is possible that two few subjects responded sufficiently well in the first place to demonstrate any effects of booster sessions on relapse. However, one can at least conclude that subjects in the booster conditions made no further gains with the additional intermittent treatment, an interesting finding itself. A major finding of the present study was that those subjects who were classified as good responders to initial treatment remained improved dur-
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ing the booster/follow-up period and that subjects who failed to respond well to treatment continued to be depressed during the booster/followup phase. This differential long-term outcome was not simply a reflection of differences in initial depression level. It should be noted, however, that the allocation of subjects to booster conditions did not take account of individual treatment response. Unfortunately, the random allocation resuited in an unequal distribution of subjects in each experimental condition according to level of improvement, precluding a definitive conclusion regarding the effect of the three booster conditions when taking initial treatment response into account. One tentative conclusion is that regardless of booster sessions or booster type, subjects who improve during treatment remain improved. A large proportion of subjects (46.4-60.7%, depending on the criterion) reported depressive symptoms during the booster/follow-up phase. Unfortunately, there are very few studies of cognitive-behavior therapy against which this result can be compared. Kovacs et al. (1981) report that 44% of their subjects were symptomatic during a one-year follow-up. Kornblith et al. (1983) found that 18 out of 34 subjects (52.9%) experienced at least one episode of depression during a 3-month period following self-control treatments with similar success rates as obtained in the present study. Teasdale, Fennell, Hibbert, and Amies (1984) report that 6 out of 16 subjects (37.5%) obtained a BDI score of >_-14 at a 3-month follow-up. Our criterion for chronic depression produces figures comparable to these studies, while our less stringent criterion is higher than all of these studies, possibly because of the lower initial success rate. Unfortunately, the criteria employed in these studies vary widely, making meaningful comparisons rather difficult. In addition, the figures in these studies probably include a proportion of subjects who did not respond well to treatment in the first place. The results of the present study underscore the need to examine the course of initial treatment responders and nonresponders separately. The mood rating results are inconsistent with previous studies (Larcombe & Wilson, 1984; Wilson et al., 1983), in which ratings of worst mood paralleled the BDI results. It is possible that stronger treatment effects are required before changes on specific symptoms are revealed. However, the follow-up results suggest that these mood ratings may be not as reliable as previously considered. In conclusion, the results provide qualified support for the short- and long-term efficacy of group cognitive-behavioral treatment for depression. Contrary to the frequently expressed recommendation that booster sessions may be an important maintenance strategy, the present findings suggest that this may not be the case. When clinically significant effects are obtained, these effects tend to be maintained. It appears that without good initial treatment response, improvement in the longer term is much less likely to occur. This study is not without its methodological problems, including the small sample size, the use of only one therapist, the heavy reliance on a self-report measure of depression, and the interpretative difficulties caused by the poor initial treatment response. However, the
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results of the present study suggest that attention should be given to understanding the reasons for the variation in treatment response between studies (and between individuals). Most importantly, we urge researchers to report on the subsequent course of depression in subjects identified as responders or nonresponders.
REFERENCES Beck, A. T., Rush, A. J., Shaw, B. F., & Emery, G. (1979). Cognitive therapy of depression. New York: Guilford. Beck, A. T., Ward, C. H., Mendelson, M., Mock, J., & Erbangh, J. (1961). An inventory for measuring depression. Archives of General Psychiatry, 4, 561-571. Blaney, P. H. (1981). The effectiveness of cognitive and behavioral therapies. In L. P. Rehm (Ed.), Behavior therapy for depression: Present status and future directions. New York: Academic Press. Cochran, W.G. (1950). The comparison of percentages in matched samples. Biometrika, 37, 256-266. de Jong, R., Henrich, G., & Ferstl, R. (1981). A behavioural treatment programme for neurotic depression. Behavioural Analysis and Modification, 4, 267-274. Dunn, R. J. (1979). Cognitive modification with depression-prone psychiatric patients. Cognitive Therapy and Research, 3, 307-317. Feighner, J. P., Robins, E., Guze, S. B., Woodruff, R. A., Winokur, G., & Munoz, R. (1972). Diagnostic criteria for use in psychiatric research. Archives of General Psychiatry, 26, 57-63. Hays, W. L. (1963). Statistics for psychologists. New York: Holt, Rinehart & Winston. Kornblith, S. J., Rehm, L. P., O'Hara, M. W., & Lamparski, D.M. (1983). The contribution of self-reinforcement training and behavioral assignments to the efficacy of self-control therapy for depression. Cognitive Therapy and Research, 7, 499-528. Kovacs, M., Rush, A. J,, Beck, A. T., & Hollon, S.D. (198 l). Depressed outpatients treated with cognitive therapy or pharmacotherapy. Archives of General Psychiatry, 38, 33-39. Larcombe, N. A., & Wilson, P. H. (1984). An evaluation ofcognitive-behaviourtherapy for depression in patients with multiple sclerosis. British Journal of Psychiatry, 145, 366-371. Lewinsohn, P. M., Biglan, A., & Zeiss, A.M. (1976). Behavioral treatment of depression. In P. O. Davidson (Ed.), The behavioral management of anxiety, depression and pain. New York: Brunner/Mazel. Lunney, G.H. (1970). Using analysis of variance with a dichotomous dependent variable: An empirical study. Journal of Educational Measurement, 7, 263-269. McLean, P. D., & Hakstian, A. R. (1979). Clinical depression: Comparative efficacy of outpatient treatments. Journal of Consulting and Clinical Psychology, 47, 818-836. Miller, R. G. (1966). Simultaneous statistical inference. New York: McGraw-Hill. Rehm, L. P. (1981). Assessment of depression. In M. Hersen & A. S. Bellack (Eds.), Behavioral assessment: A practical handbook. New York: Pergamon Press. Rehm, L. P.,Kornblith, S. J., O'Hara, M. W., Lamparski, D. M., Romano, J. M., & Volkin, J.I. (1981). An evaluation of major components in a self-control therapy program for depression. Behavior Modification, 5, 459-489. Rush, A. J., Beck, A. T., Kovacs, M., & Hollon, S. (1977). Comparative efficacyof cognitive therapy and pharmacotherapy in the treatment of depressed outpatients. Cognitive Therapy and Research, 1, 17-37. Teasdale, J. D., Fennell, M. J. V., Hihbert, G. A., & Amies, P.L. (1984). Cognitive therapy for major depressive disorder in primary care. British Journal of Psychiatry, 144, 400406.
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Wilson, P.H. (1982). Combined pharmacological and behavioural treatment ofdepression. Behaviour Research and Therapy, 20, 173-184. Wilson, P. H., Goldin, J. C., & Charbonneau-Powis, M. (1983). Comparative efficacy of behavioral and cognitive treatments of depression. Cognitive Therapy and Research, 7, 111-124. RECEIVED"August 9, 1984 FINAL ACCEPTANCE:January 24, 1985