ECRI's analysis of all the available evidence found that medication used to treat bulimia nervosa reduced the frequency of binge eating and purging in the short term (a few months). Long-term data are not available. Medication also lessened anxiety, depression, and eating disorder psychopathology (abnormal behavior). Cognitive behavioral therapy (CBT) reduced the frequency of purging, and it did so more effectively than medication. However, the effect of CBT on binge eating itself, and on anxiety, depression, and eating disorder psychopathology is not clear from the available evidence. The effectiveness of other kinds of psychotherapy is also unclear at this time. More clinical research of high quality is needed to answer the questions that remain about how well CBT and other kinds of psychotherapy, and medications work for bulimia nervosa.

Trials on complementary therapies and alternative therapies for bulimia nervosa either did not exist or were of such poor quality that they could not be analyzed—so it was not possible to determine whether or not they work.

How we came to these conclusions

1. Is drug therapy effective treatment for bulimia nervosa?
2. Is psychotherapy or other non-drug therapy effective treatment for bulimia nervosa?
3. Is psychotherapy therapy or other non-drug therapy more effective than drug therapy for the treatment of bulimia nervosa?
4. Is CBT (the most commonly used form of psychotherapy today) more effective than other types of psychotherapy for the treatment of bulimia nervosa?

Whenever possible, ECRI's analysts conducted a type of statistical analysis that pools data from several clinical trials on the same treatment to better enable researchers to figure out what's going on. For drug studies, they analyzed whether drugs were more effective than placebo (an inactive pill). For psychotherapy, they analyzed whether CBT (the therapy for which the most data were available) was better than no treatment and how it compared to drug therapy and other types of psychotherapies.

The effect of drug therapy and psychotherapy on each of these outcomes was analyzed:

• Frequency of bulimic behavior (bingeing and compensatory behavior)
• Patient quality of life
• Mood and anxiety levels
• Eating disorder psychopathology (for example, body image dissatisfaction and eating attitudes)
• Personality and interpersonal functioning (for example, anxiety and depression measures, self-esteem measures, and family environment scales)
• Patient mortality

For studies on the prescription drugs used to treat bulimia nervosa, we first wanted to find out whether the various types of drugs that are used for bulimia nervosa differed from each other in effectiveness. We performed exploratory analyses to examine this issue and found that the different types of prescription drugs used to treat bulimia nervosa did not appear to differ significantly in their effectiveness or acceptability to patients. Based on this analysis, we pooled data from studies on different types of prescription drugs into one analysis.

Studies on psychological treatments presented a different problem. Unlike individual drug studies, which studied only one drug, individual studies on psychological therapy often used more than one type of psychological therapy in a single trial. Psychological therapy was also delivered in individual and group settings, which could theoretically affect how well the therapy works. Thus, analysts had to adopt different analytic approaches to analyze data from these studies.

What are the main results of the analysis?

The analysis found that drug therapy for bulimia nervosa reduced some patients'underlying anxiety and depression, eating-disorder psychopathology, and binge-eating and purging frequency. Whether or not drug therapy improved patients' quality of life could not be determined from the available data. These findings were obtained by pooling data from the 26 RCTs that compared drug therapy to a placebo (inactive pill). This is the type of comparison needed to learn whether drugs really work.

Is psychotherapy effective treatment for bulimia nervosa?

The analysis found that for some patients, CBT reduced purging behavior. However, the evidence was inconclusive on whether CBT improved patients' quality of life or reduced underlying eating disorder psychopathology, binge-eating behavior, or depression and anxiety. Also, determining whether the effectiveness of CBT changed when it was delivered in different formats could not be determined because too few studies were available to allow meaningful analysis of different CBT formats. This answer was obtained by pooling data from 11 RCTs that compared CBT to no therapy (individuals on a wait list).

Is psychotherapy more effective than prescription drug therapy for treatment of bulimia nervosa?

The analysis found that CBT was more effective than drug therapy for reducing purging behavior. The evidence was inconclusive on whether CBT was more effective than drug therapy for improving quality of life, reducing underlying eating disorder psychopathology, binge-eating behavior, or depression or anxiety,. This answer was obtained by pooling data from 6 RCTs that compared the effectiveness of CBT to drug therapy. To better answer this question, more data from appropriately designed comparative studies are needed.

Is CBT, in particular, more effective than other types of psychotherapy for treatment of bulimia nervosa?

The results of this analysis were inconclusive because too few data were available for analysis. Data were available from 13 RCTs that compared CBT to other psychotherapies. CBT was compared to behavioral therapy in 3 studies, and it was compared to interpersonal therapy in 2 studies. We tried to pool the data to obtain an answer, but too few data of sufficient quality were available. To satisfactorily answer this question, more data from appropriately designed controlled trials are needed.

Click here to access the 650-page evidence report describing the details and methods of all of these analyses or its Executive Summary.