Psychotherapy of bulimia nervosa: what is effective? A meta-analysis.

The present paper assesses the state of the art of psychotherapy of bulimia nervosa. Five hundred and fifty publications available up to April 1990 were systematically screened. Included in subsequent analysis were all studies with samples of five or more bulimic patients which used operational diagnostic criteria, and reported results of binging and vomiting or other means of purging quantitatively. Only 18 independent studies with a total of 433 patients in 24 treatments and 61 patients in 6 control groups fulfilled these criteria. Therapy outcome across studies was assessed meta-analytically. Therapy process across studies was assessed through ratings of interventions used (behavioural, cognitive, educational, humanistic, psychodynamic techniques and symptom-, conflict-, and relationship-orientation), setting and dose parameters. Settings were out-patients only, mostly group or individual. Most studies were on short-term therapies and follow-ups. Stepwise regression analysis revealed no definite advantage of one setting or therapeutic approach over another. Thirty-six per cent of variance was explained by the number of treatment sessions in combination with relationship orientation.