Behav. Res. Ther. Vol. 32, No. I. pp. 3745, 1994 ooO5-7967/94 %6.00 +O.OO Printed in Great Britain. All rights reserved Copyright 0 1993 Pergamon Press Ltd

COMPARISON OF COGNITIVE-BEHAVIOR THERAPY AND DESIPRAMINE IN THE TREATMENT OF BULIMIA

NERVOSA

HAROLD LEITENBERG,* JAMES C. ROSEN, JANE WOLF, LINDA S. VARA, MARK J. DETZER

and DEBRA SREBNIK

Department of Psychology, University of Vermont, Dewey Hall, Burlington, VT 054050134, U.S.A.

(Received 18 December 1992)

Sununary-A comparison of cognitive-behavior therapy alone, desipramine alone, and cognitive-behavior therapy combined with desipramine was made in the treatment of bulimia nervosa. The study was terminated early with an N of only 7 subjects per condition because of a high drop-out rate and lack of positive response in the desipramine alone group compared to the other two groups. By this time it was also apparent that at posttreatment and at 6 months follow-up no benefit was being realized from combining cognitive-behavior therapy with desipramine.

INTRODUCTION

Two different approaches to the treatment of bulimia nervosa have received the most empirical support in controlled outcome studies. These are cognitive-behavior therapy and antidepressant medication. Cognitive-behavior therapy has been shown to be more effective than waiting list controls in a series of different studies (cf. Agras, Schneider, Arnow, Raeburn & Telch, 1989; Lacey, 1983; Lee & Rush, 1986; Leitenberg, Rosen, Gross, Nudelman & Vara, 1988; Ordman 8z Kirschenbaum, 1985; Wolchik, Weiss & Katzman, 1986). It has also been demonstrated to be more effective than nondirective therapy (Kirkley, Schneider, Agras & Bachman, 1985), structured individual psychotherapy (Fairburn, Kirk, O’Connor & Cooper, 1986) and interpersonal psycho- therapy (Fairburn, Jones, Peneler, Carr, Solomon, O’Connor, Burton & Hope, 1991). Similarly a number of double-blind controlled drug studies have shown that antidepressant medication is more effective than placebo (Agras, Dorian, Kirkley, Arnow & Bachman, 1987; Barlow, Blouin, Blouin & Perez, 1988; Fluoxetine Bulimia Nervosa Collaborative Study Group, 1992; Horne, Ferguson, Pope, Hudson, Lineberg, Ascher & Cato, 1988; Hughes, Wells, Cunningham & Ilstrup, 1986; Kennedy, Piran, Warsh, Prendergast, Mainprize, Whynot & Garfinkel, 1988; Mitchell & Groat, 1984; Pope, Hudson, Jonas & Yurgelun-Todd, 1983; Pope, Keck, McElroy & Hudson, 1989; Walsh, Stewart, Roose, Gladis & Glassman, 1984; Walsh, Hadigan, Devlin, Gladis & Roose, 1991).

The results from these controlled cognitive-behavior therapy and antidepressant medication studies are similar. For example, at the end of treatment binge-purging episodes decreased by approx. 64% on average in the drug treatment studies and 78% in the cognitive-behavior therapy studies. In addition approx. 3 1% of the Ss in the drug studies had completely ceased binge-eating and purging compared to approx. 39% of Ss in the cognitive-behavior therapy studies. One important difference, however, is that in the cognitive-behavior therapy studies outcome was typically assessed after therapy had been discontinued whereas in the drug studies outcome was typically assessed while medication was still being administered. Clinical reports suggested that a substantial relapse will occur when medication is discontinued (Pope, Hudson, Jonas & Yurgelun- Todd, 1985) and more recent research has confirmed this (cf. Pyle, Mitchell, Eckert, Hatsukami, Pomeroy & Zimmerman, 1990; Walsh et al., 1991).

Despite the positive findings from these two types of treatments, the outcomes are still far from optimal since only between 10 and 65% of patients completely stop purging during treatment. One obvious question is whether or not the combination of cognitive-behavior therapy and antidepress- ant medication would be more effective than either alone. Also direct comparisons of the relative

*Author for correspondence.

37

38 HAROLD LEITENBERG et al.

effectiveness of each of these treatments need to be made, both while treatment is still in effect and after it has ended.

When we first started this study no prior research comparing the effectiveness of cognitive- behavior therapy and drug treatment for bulimia nervosa had been published. Since then, however, two studies have been reported with slightly different results. In the first study, Mitchell, Pyle, Eckert, Hatsukami, Pomeroy and Zimmerman (1990) found that an intensive 12 week program of cognitive-behavior therapy delivered in a group format was more effective on multiple outcome measures than imipramine even though imipramine was more effective than placebo. Moreover, imipramine with cognitive-behavior therapy was not more effective in changing eating and purging behavior than cognitive-behavior therapy alone. Accordingly these authors concluded that cognitive-behavior therapy was more effective than antidepressant medication in the treatment of bulimia nervosa and there was no benefit to combining the two forms of treatment. In the second study, Agras, Rossiter, Arnow, Schneider, Telch, Raeburn, Bruce, Per1 and Koran (1992) compared desipramine alone (for 16 or 24 weeks); desipramine combined with cognitive-behavior therapy (for 16 or 24 weeks); and cognitive behavior therapy alone (for 16 weeks plus three additional sessions at weeks 20, 24 and 28). There was no placebo group. Two assessments were conducted, one at 16 weeks and one at 32 weeks after all treatments had been discontinued. At 16 weeks, both the cognitive-behavior therapy alone and combined treatment conditions showed significantly greater reductions in binge-eating and purging than the desipramine alone condition and there was no significant difference between the cognitive-behavior therapy alone condition and the combined conditions. These results are thus very similar to those of Mitchell et al. (1990). At 32 weeks, the 24 week combined condition showed significantly greater reductions in binge-eating and purging compared to the 16 week medication alone condition. The cognitive-behavior therapy alone condition however was no longer significantly different from the 16 week medication alone condition. The authors therefore concluded that a combination of medication and cognitive-behav- ior therapy may be the preferred treatment for bulimia nervosa. However, although their results support the conclusion that the combined condition is superior to medication alone, they do not support the conclusion that the combined condition is superior to cognitive-behavior therapy alone. The combined condition did not significantly differ from the cognitive-behavior therapy alone group at any time on binge-eating or purging behavior. In addition, the results of Mitchell et al. (1990) also suggest otherwise, i.e. no gain from combining medication plus cognitive-behavior therapy over cognitive-behavior therapy alone.

The present study was also designed to compare the effectiveness of cognitive-behavior therapy and desipramine for treatment of bulimia nervosa, both to each other and to a condition in which the two treatments were combined. We originally chose to examine desipramine because when we started this study it had been reported to have the most impressive effects on bulimia nervosa of any of the antidepressant medications that had been examined up to that point, including imipramine (Hughes et al., 1986).

METHOD

Subjects

To be included in this study, potential Ss had to be female, 18-45 yr of age, within 8&120% of normal weight as defined by the 1983 Metropolitan Life Insurance tables, and meet DSM-III-R and Russell’s (1979) criteria for bulimia nervosa. The Eating Disorders Examination (Cooper & Fairburn, 1987), a 1 h structured interview was used to determine if 5’s met the diagnostic criteria for bulimia nervosa. Exclusionary criteria included a current diagnosis of bipolar disorder, schizophrenia, anorexia nervosa, cardiac or hepatic disease, pregnancy or plan for same in the next 6 months, abnormal values of electrolytes or serum glucose, chemical dependency or serious suicide risk. The Ss were also excluded if they were involved in simultaneous treatment of any kind including antidepressant medication and if they had been previously treated for bulimia nervosa with cognitive-behavior therapy or desipramine.

The Ss were recruited through newspaper advertisements and professional referrals. The study was advertised as a joint project of the Departments of Psychiatry and Psychology at the University

Treatment of bulimia nervosa 39

of Vermont. It is noteworthy that 15% of the people who initially inquired about participating in the study imm~iately refused to consider it further because they did not wish to chance being assigned to one of the conditions involving medication. No one refused to participate because they might not get medication.

If potential Ss met the screening criteria they were asked to complete a battery of self-report questionnaires and to record their daily eating and vomiting behavior for two consecutive weeks on a standard form provided to them. In addition to meeting DSM-III-R criteria, they also had to vomit at least 4 times during this two-week period to be eligible for the study.

We originally planned to randomly assign 12 patients to each of the three treatment conditions: cognitive-behavior therapy alone, desipramine alone, and cognitive-behavior therapy combined with desipramine. Although this is an arguable ethical issue, we elected to omit no treatment and placebo control conditions in this study in the belief that sufficient evidence had already been gathered in the literature demonstrating the effectiveness of both cognitive-behavior therapy and desipramine relative to these controls, and that therefore it might no longer be justifiable to withhold these treatments.

As will be described in the results section, the study was terminated earlier than originally planned because of a high drop-out rate and lack of positive response in the Ss who completed the desipramine alone condition. By this time there was also clear evidence that the combined condition was not resulting in greater improvement than the cognitive-behavior therapy alone condition. As a result, only 7 Ss were assigned to each condition.

Procedure and description of treatment conditions

Following the pretreatment assessment phase Ss were randomly assigned to one of the three treatment conditions.

Cognitive-behavior therapy alone condition. The Ss assigned to this condition received 22 individual cognitive-behavior therapy sessions. Therapists were I-IL, JR and LV, each of whom had considerable experience with cognitive-behavioral treatment of bulimia nervosa. In order to further insure adherence to the treatment protocol, a detailed manual was employed and weekly meetings were held to discuss ongoing therapy issues with the patients that were being seen. There were two treatment sessions a week for the first two weeks followed by 18 weekly sessions or a total of 22 treatment sessions over 20 weeks. Sessions typically lasted l&2 h.

The cognitive-behavior therapy protocol for bulimia nervosa that we employed has been described in detail elsewhere (Rosen & Leitenberg, 1985) and the manual used in this study is available from the authors upon request. It is a combination of the standard cognitive-behavior therapy package for bulimia nervosa (Fairburn, 1985) supplemented with exposure to eating feared foods during therapy sessions without recourse to vomiting immediately afterwards. Its effective- ness relative to no treatment and to cognitive-behavior therapy without exposure plus response prevention has been previously described (cf. Leitenberg et al., 1988; Leitenberg & Rosen, 1989).

Desipramine alone condition. The Ss assigned to this condition met weekly with the team psychiatrist (JW), who had extensive clinical experience with pharmacologic treatment of bulimia nervosa. The first session lasted 1 h and provided an explanation and rationale for treating bulimia nervosa with desipramine. Potential beneficial effects and possible side effects were discussed. After the first session patients met once a week for 20 weeks to go over any possible negative side effects they were having. These sessions were limited to 15 min. No advice about eating, dieting, binges or purging was provided. There was no daily self-monitoring of eating behavior and no discussion of cognitive distortions, body image concerns, antecedents to binge-purge episodes, etc. These sessions were strictly medicated oriented and provided very little, if any, psychotherapy support.

Patients were started at 50 mg at bedtime and dosage was increased by 50 mg every 3 days until 150 mg was reached. After 5-7 days at that dosage serum blood levels were drawn and dosage was thereafter adjusted to achieve a serum level between 150 and 275 ng/ml. Serum blood levels were taken periodically during the 20 week period to insure blood levels were being maintained. For the Ss who remained in treatment the mean blood serum levels of desipramine following stabilization ranged from a low of 170 ng/ml to a high of 210 ng/ml. Compared to the two most recent studies which used desipramine in the treatment of bulimia nervosa, this is a somewhat

40 HAROLD LEITENBERG et al.

higher blood serum level than that reported by Agras et al. (1992) and a somewhat lower level than that reported by Walsh et ai. (1991).

Combined condition. In the combined condition Ss received the identical treatments described earlier except they were added together. Thus each week Ss in this condition saw one therapist for CBT (either HL, JR or LV) for I$ h and the team psychiatrist for 15 min to go over medication issues. For Ss who remained in treatment in this condition the mean blood serum levels of desipramine following stabilization ranged from a low of 175 ng/ml to a high of 446 ng/ml. This latter S was anomalous as she consistently had a very high blood level of desipramine even though her dosage was only 100 mg and she had no negative side effects. She may have loaded up prior to each blood draw but she denied this.

Measures

We had Ss monitor their eating and purging behavior for two consecutive weeks at four points in time: pretreatment, end of treatment (during the last two weeks of treatment), posttreatment (two weeks following the end of treatment), and at six-month follow-up. In daily records of their eating and vomiting, Ss recorded the type and amount of food and liquid they bad consumed, and whether they considered each eating episode to be a binge and if it was followed by vomiting. As in earlier studies binging was highly correlated with purging and is therefore not reported separately. The mean weekly frequency of vomiting was calculated from 2 weeks of these diaries at each assessment phase.

A battery of questionnaire measures was also administered at three points in time: pretreatment, end of treatment, and at 6-months follow-up after treatment had ended. The questionnaires included the Eating Attitudes Test (EAT; Garner & Garfinkel, 1979), the Brief Symptom Inventory (BSI: Derogatis & Spencer, 1982), the Rosenberg Self-Esteem Scale (Rosenberg, 1979); The Body Shape Questionnaire (BSQ; Cooper, Taylor, Cooper & Fairburn, 1987) and the Inventory to Diagnose Depression (IDD; Zimmerman & Coryell, 1987). The IDD was selected because it permits diagnosis of major depression by DSM-III-R criteria (agreement with the Diagnostic Interview Schedule was reported to be 97%) as well as a rating of severity of depression which is highly correlated with the Beck Depression Inventory (0.87).

RESULTS

Prior to treatment the three groups were very similar in their demographic backgrounds, bulimia nervosa history and severity, and more general psychological symptoms. They did not significantly differ on such demographic variables as age (mean was 26.7 yr for the full sample), marital status, education level, or current weight. There also was no significant difference on duration of disorder (mean of 83.48 months for the full sample) or number of binge-purge episodes per week recorded during pretreatment (mean vomiting episodes per week for the full sample was 8.5, see Table 1). There was also no significant difference on any of the six different questionnaire measures on which the groups could be compared at pretreatment, see Table 2.

At the end of the first treatment session, Ss completed a single item credibility questionnaire. They were instructed to fill this out confidentially and to return it to the research assistant in a preaddressed envelope. The question asked “how much do you think this treatment will help you?” and Ss responded on a 7-point scale (1 = “very little” and 7 = “very much”). The mean credibility ratings were 6.45, 4.75 and 5.50 respectively for the cognitive-behavior therapy alone condition, the desipramine alone condition, and the combined condition. These ratings were not statistically significantIy different, 1;(2,18) = 2.41, P = 0.12.

Table 1 shows the mean number of purge episodes per week for each S in each condition at each assessment phase. Because the N per group was small, data for each individual S as well as group means are shown. Perhaps the most striking result was the high proportion of drop-outs in the desipramine group. Four out of seven Ss initially assigned to the desipramine alone condition dropped out of the study compared to only one in the cognitive-behavior therapy condition. Of the four drop-outs in the desipramine group, one discontinued after the first week on medication, another after the second week, another after the fourth week and another after the eighth week. None had reported improvement in bulimia symptoms and each said they wanted to discontinue

Treatment of bulimia nervosa 41

medication because of various negative side effects and/or because they really wanted something more than just medication. Attempts to adjust dosages and educate patients about side effects were to no avail. In the combined condition there were also two dropouts because of medication complaints, one after the first week and another after the third week. A third S in this condition (S 4 in Table 1) afso refused to continue taking desipramine after the ninth week but wanted to continue with cognitive-~havior therapy. We allowed this and her data are still included as part of the combined group because it could be argued that she had been on medication long enough for it to have had a therapeutic effect.

As indicated in Table 1 five cut of the six Ss who completed the cognitive-behavior therapy condition had stopped vomiting by the last two weeks of treatment and the remaining S who completed treatment in this condition only vomited once in two weeks. By contrast none of the three Ss who completed the trial with desipramine stopped vomiting completely and only one showed any subs~ntial decline. After medication was discontinued, however, this patient was still vomiting at a rate of 34 times per week. In the combined condition four out of the five Ss who completed treatment had stopped vomiting by the end of treatment, with the remaining S showing no benefit. After medication was withdrawn two of the Ss who had stopped vomiting rebounded slightly, one vomiting once per week and the other two times per week.

Results were generally maintained at the 6-month follow-up. In the cognitive-behavior therapy group four of the Ss did not vomit at all. The remaining two S’s showed more of a relapse in that one vomited twice per week and the other 3-4 times per week (in pretreatment, however, this S had vomited 19-20 times per week). In the combined condition two Ss were still not vomiting, one vomited only once in two weeks, and two showed signs of relapse, vomiting 2-3 times and 5-6 times respectively per week. The three Ss who completed the drug alone condition vomited 12-13, 4 and 5 times per week respectively during follow-up. It might be noted that all 3 of these Ss obtained additional treatment of various sorts during the follow-up period. One S in the cognitive-behavior therapy alone condition and one S in the combined condition also sought further treatment during the follow-up period,

Because of the small number of Ss who completed treatment in the desipramine alone group a statistical comparison of posttreatment and follow-up data between the groups is not meaningful. We were, however, able to perform within group If-tests which showed a significant

Table I. Mean number of vomiting episodes per week for each S in each treatment condition at pretreatment, end of treatment, posttreatment, and follow-up

Pre- End of Post- treatment treatment treatment Follow-uu

Cog~iti~-be~vio~ therapy Subjects: 1

2 3 4

6 7

Mean Desipramine

Subjects: I 2 3 4 5 6

Mean Cognitive-behavior therapy and desipramine combined

Subjects: I 2

4’

6 7

9.50 Drop-out 11.00 0.0 13.50 0.0 19.50 0.0 3.00 0.0 3.50 0.50 5.00 0.0 9.29 0.08

Drop-out 0.0 0.0

;.&I 0.50 0.0 0.0 0.33

Drop-out 0.0 0.0 3.50 0.0 2.00 0.0 0.92

9.50 Drop-out Drop-out Drop-out 2.50 Drop-out Drop-out Drop-out 8.50 Drop-out Drop-out Drop-Out

15.50 13.00 12so 12so 9.00 1.50 3.50 4.00 5.00 Drop-out Drop-out Drop-out

14.00 10.00 11.50 5.00 9.14 8.17 9.16 7.17

8.00 II.00 7.00 2.00 5.00 3.00

14m 7.14

8.50

iif: 0.0

Drop-out 0.0

Drop-out I .70

9.00 2.00 1.00 0.0

Drop-out 0.0

LJrop-oui 2.40

2.50 0.50 5.50 0.0

Dropout 0.0

DtVp-OUI 1.70

*Subject 4 in the combined condition discontinued medication in the 9th week but continued cognitive-behavior therapy.

42 HAROLD LEITENBERG et al.

Table 2. Mean scores for each treatment condition on questionnaire measures at pretreatment, end of treatment, and follow-up

End of Pretreatment treatment Follow-up

M M P M P-

Cognirive -Behavior Therapy :

EAT BSI

BSQ IDD Self-esteem

Desipramine : EAT BSI

BSQ IDD Self-esteem

41.60 14.67 0.01 I.14 0.21 0.05

112.17 69.61 0.02 27.50 8.17 0.03 26.67 32.83 0.02

55.67 47.00 NS I .73 1.13 NS

131.00 127.33 NS 32.00 21.00 0.03 25.00 25.61 NS

12.60 0.02 0.16 NS

61.40 0.04 8.80 0.04

35.20 0.03

41 Ml NS 1.36 NS

141.67 NS 20.67 0.03 23.67 NS

Combined: EAT 62.60 26.40 0.00 36.80 0.02 BSI 1.77 0.64 0.02 0.92 0.05 SSQ 169.20 89.00 0.00 104.60 0.01 IDD 36.20 18.20 0.02 19.80 NS Self-esteem 20.20 28.60 0.03 27.00 NS

EAT, Eating Attitude Test Total scow BSI, Brief Symptom Inventory, Global Severity Index; BSQ, Body Shape Questionnaire; IDD, Inventory to Diagnose Depression. The means in this table are only for those Ss who completed each treatment: the N was 6 for the cognitive-behavior therapy group, 3 for the desipramine group, and 5 for the combined group.

reduction in vomiting frequency from pretreatment to follow-up for both the cognitive-behavior therapy alone condition, t( 1,5) = 3.41, P = 0.02, and for the combined condition, t(1,4) = 2.73, P = 0.05, but not for the desipramine alone condition, t( 1,2) = 3.21, P = 0.09.

The questionnaire measures yielded similar results. The mean scores for the Ss in each group who completed treatment are shown in Table 2. On every measure the cognitive-behavior therapy group showed significant improvement from pretreatment to the end of treatment. These gains were sustained at 6 months follow-up with the exception of the BSI where the P value was only 0.07. By contrast the means for the 3 5s who completed the desipramine alone treatment were not significantly different at the end of treatment or at follow-up from the means at pretreatment, except for depression. The questionnaire results for the combined group were more similar to that of the cognitive-behavior therapy group than to the desipramine alone group in that all measures showed a significant reduction from pretreatment to the end of treatment. However, at follow-up the depression and self-esteem scores were no longer significantly different from pretreatment.

DISCUSSION

The effectiveness of therapy can be judged not only by the results obtained from people who complete treatment but also by the percentage of people who refuse a particular treatment or drop-out without apparent benefit. When these are considered together the results of the present study suggest that cognitive-behavior therapy alone is more effective than desipramine alone, at least as they were administered here. Furthermore, combining these two forms of treatment did not improve the results obtained with cognitive-behavior therapy alone.

The basic findings of this study are consistent with those recently reported by Mitchell et al. (1990) in their comparison of cognitive-behavior therapy with another antidepressant medication, imipramine. These investigators, with a much larger number of Ss per condition, also found that cognitive-beha~or therapy was more effective than imipramine alone and that the combination of the two was no more effective than cognitive-behavior therapy alone. Agras et al.‘s (1992) findings with desipramine, on the other hand, were more mixed: at 16 weeks they were similar to that of the present study and to Mitchell et al.‘s (1990) results in that cognitive-behavior therapy alone and cognitive-behavior therapy combined with medication were equally effective in suppressing binge-eating and purging and each was more effective than medication alone. After 24 weeks of medication, however, only the combined condition was more effective than medication alone,

Treatment of bulimia nervosa 43

though there was still no significant difference in binge-eating and purging between the groups receiving cognitive-behavior therapy alone and cognitive-behavior therapy with desipramine. It would, therefore, seem that the weight of the evidence so far across studies does not favor routinely combining medication with cognitive-behavior therapy in the treatment of bulimia nervosa. It certainly does favor, however, cognitive-behavior therapy either alone or in combination over a single tricyclic antidepressant medication alone.

The differential drop-out rate in the present study deserves special mention. Four out of the seven Ss in the drug alone condition dropped out of treatment because they said they did not like the medication ostensibly because of negative side effects. In the combined condition two Ss dropped out with the same complaint and an additional S in this condition refused to take further medication after the ninth week. This represents 50% of the people assigned to receive medication. Even during the recruitment phase 15% of potential Ss said they did not wish to participate in the study if it meant that they might receive only drug treatment. Clearly there was a lot of resistance to the use of drugs in this sample. Barlow et al. (1988) also reported a high drop-out rate (48%) in their study comparing desipramine to placebo and 35% of these drop-outs cited drug side effects as the reason for discontinuing treatment. Similarly, in the Walsh et al. (1991) study 23% of the Ss in the desipramine condition dropped out of treatment in the first 6 weeks, and in the Agras et al. (1992) study, 17% had stopped medication by 24 weeks compared to only one S who had stopped treatment in the cognitive-behavior treatment condition. In the Mitchell et al. (1990) study with imipramine, 43% of the Ss in the drug only group failed to complete treatment compared to 16% who were in the placebo plus cognitive-behavior therapy condition.

The results in the medication alone group in the present study were much poorer than expected based on the earlier findings with desipramine reported by Hughes et al. (1986) though they are not disparate from the more recent findings of Barlow et al. (1988) and Walsh et al. (1991) who respectively reported remission rates of only 11% and 12.5% in their desipramine alone groups. Also Walsh et al. (1991) reported a mean reduction in binge frequency of only 47%.

Since two of the investigators in the present study (HL & JR) have a long history of doing cognitive-behavioral treatment research with bulimia nervosa, one hypothesis for these findings is that our Ss may have been biased in favor of the cognitive-behavior treatment due to the reputation of the investigators. However, Ss were mainly recruited through newspaper advertisements which emphasized that this was a joint project of the Departments of Psychiatry and Psychology and the psychiatrist on this project (JW) was considered in our community at least as much an expert on eating disorders as we were; she ran both an inpatient and outpatient program for eating disorders in which medication was often included in treatment. In terms of our own biases affecting these results, all we can say is that our initial expectations when we started this study were that the combination condition would have the best results. Beyond that, it should be noted that the measures were filled out by Ss not by therapists and these questionnaires and self-recording forms were returned to research assistants not to the therapists.

It could justifiably be argued that the way desipramine was administered in ths study was not the way drug treatment is typically prescribed in a psychiatric setting and that is why the results were so poor. In order to examine the “pure” treatment effects of the drug, no psychotherapy of any kind accompanied the drug treatment in the desipramine alone condition. Also, in actual clinical practice if a bulimia nervosa patient did not respond to one drug she would usually be switched to a different drug. Restrictions of the research protocol, however, prevented this flexibility and as a result may have limited the potential effectiveness of drug treatment.

It should be noted, however, that the constraints of research also limited the administration of cognitive-behavior therapy so that it too was not conducted in a clinically typical or optimal way. Rigidly attempting to follow a treatment manual for a fixed number of sessions is not the way most clinicians function in actual practice. Nevertheless the outcomes were quite positive in the cognitive-behavior therapy condition in comparison to the desipramine condition despite these limitations. For example, during the last 14 days of treatment five out of the six Ss still in treatment in this condition did not purge at all and the remaining S did so only once. Moreover at 6 months follow-up four of these SS were still not vomiting at all and in the remaining two Ss vomiting was reduced by 77% from pretreatment levels. It should also be noted that the Ss in the cognitive-be- havior therapy condition not only showed substantial gains in their eating behavior but also showed

44 HAROLD LEITENBERG et al.

significant reduction in general psychological symptomatology and in depression. Dysfunctional attitudes about eating and weight and body shape were also significantly improved. In contrast, only depression showed a substantial decline for the three Ss who completed treatment in the desipramine alone condition.

Obviously, it could always be argued that the findings would have changed if we did not stop the study when we did. However, there was no indication in the data to support such a prediction and, to the contrary, we felt further random assignment to the drug alone condition as it was being administered in the present study was not ethically justifiable given the high drop-out rate and the clearly more positive results of the other two conditions.

Walsh et al. (1991) in reflecting upon the results of Mitchell et al. (1990) and the relatively poor outcomes they themselves obtained with desipramine, even though superior to a placebo, questioned the effectiveness of any single tricyclic antidepressant as the sole method of treatment for bulimia nervosa. They suggest, however, that “before a definitive conclusion regarding the superiority of cognitive-behavior psychotherapy can be reached, it may be important to compare the efficacy of this form of treatment with pharmacological strategies that incorporate sequential medication trials” (p. 1211). This seems a reasonable suggestion, although presumably one might argue that in order to have a balanced design, sequential trials with alternative forms of psychotherapy might also have to be examined for those people who fail to respond to a single trial of cognitive-behavior therapy.

Acknowledgements-This study was supported in part by USPHS-GCRC-RR 109 and Merrell Dow Pharmaceutical Co.

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