Integrating Treatment in Eating Disorders

In contrast, for bulimia nervosa, the use of medication--most commonly antidepressants--in combination with psychotherapy is often useful, and there are now several published randomized, controlled trials. A recent meta-analysis (summarized in Table 2) found that where antidepressants are combined with focused psychotherapies and compared with either antidepressants alone or with psychotherapy alone, the combination is favored (Bacaltchuk et al., 2001).

How medications and psychotherapies--biological and psychological--act together to give a better outcome is unknown, but it is a phenomena not confined to eating disorders. For example, in obsessive-compulsive disorder, brain imaging changes have been reported to occur following psychological treatments (Schwartz et al., 1996). Whether similar effects occur in the treatment of patients with bulimia nervosa is speculative, but reports by Hirano and colleagues (1999) and Kaye and colleagues (2001) support further exploration of the biological mechanisms in treatment and the mode of synergy of combination therapies. In addition, the effect of antidepressants has been found across a number of trials in study subjects most often without comorbid severe depression (Bacaltchuk et al., 2000). This supports there being a specific effect in bulimia nervosa, not merely a general effect on depressive symptoms.

In these meta-analyses, however, non-completion rates are high in the groups where medications are included compared to those that have psychotherapy alone. This suggests that patients find antidepressants less acceptable than psychotherapy. Why this should be so has not been rigorously explored in treatment studies. One possibility is because of greater side effects, but it could also be because taking tablets lacks credibility for patients. It is known that a range of important personal and social-cultural factors are likely to contribute to the etiology of bulimia nervosa and similar disorders (e.g., Fairburn et al., 1998; Fairburn et al., 1997). Thus, treatments (such as CBT or interpersonal psychotherapy) that appear to address these issues are easy to explain to patients with respect to their theoretical underpinnings. Similarly, however, as already noted, there is evidence that biological mechanisms such as possible serotonin depletion (Kaye et al., 2001) are likely to also be important. Whether these changes are a cause or consequence of bulimia nervosa is unclear, but they do provide some rationale for the use of, for example, the SSRIs in the treatment of bulimia nervosa.

There are several instances where I have found it most useful to integrate an antidepressant and psychotherapy, which accords with other opinion (Garfinkel and Walsh, 1997). (I commonly use the staged and manualized form of CBT as described by Wilson et al., 1997). The first is in cases of very frequent and severe binge-eating and the antidepressant aids reduction in bingeing to a point where the patient has a greater capacity to engage in psychotherapy. This is similar to the second instance, in which the patient suffers moderate to severe depressive symptoms. The third most common situation in which I use antidepressants is when patients have made some improvement with CBT but moderate eating disorder symptoms remain. Finally, when specialized psychotherapeutic help is difficult for patients to access, primary care physicians often may commence antidepressants while awaiting a specialist opinion.

While the evidence for integrating treatments in eating disorders is not strong, there is sufficient evidence to support combining antidepressant and psychotherapies in the active treatment of bulimia nervosa. This may, however, be at the cost of people withdrawing from treatment, due possibly to side effects or the lack of treatment credibility.