Bulimia nervosa, psychological and treatment outcomes
Recent studies have provided evidence of a common trend towards the increase in time of the rates of eating disorders, especially for bulimia nervosa (BN). In European countries the prevalence of threshold-BN (patients who have been diagnosed of the full disorder) has been estimated to be between 1% and 7% in young female samples. But these indexes should be considered carefully, since the difficulty of detecting sub-clinical cases (that is, people with some symptoms but without the complete disorder, also labelled sub-threshold). The prevalence rates are significantly higher when solely considering the presence of eating symptoms or impaired eating behaviours. In fact, sub-threshold BN (sub-BN) is more common than full, threshold, BN.
Despite the prevalence and associated medical and psychiatric problems, only a small proportion of individuals with BN seek treatment. This mismatch between prevalence and treatment seeking may be due in part to difficulties in finding specialized treatment settings for this problem and the high costs and logistics associated with face-to-face individual psychotherapy. The lack of treatment response for sub-BN patients is more important, but critical for several reasons. First, research has documented the clinical significance of sub-threshold eating-related problems that have evolved from previous eating disorders. Second, there is evidence that the severity of psychopathology and degree of secondary psychosocial impairment in those with sub-BN are comparable to those seen in patients with anorexia nervosa or full BN.
The aim of our study was to compare the short-term response to a brief outpatient psycho-educational intervention in individuals with full-BN and sub-BN. This intervention consisted of six weekly outpatient sessions (90 min each) with a total of 8 to 10 patients per group. Both full-BN and sub-BN patients were treated together in this same brief outpatient group therapy, which main objective was to offer information and psycho-education about BN without going into details of the patients’ individual problems. The topics addressed included general information and negative consequences of BN, nutritional patterns and monitoring of meal plans, preventing strategies for decreasing bingeing and purging behaviour, cognitive model for the comprehension of BN, problem-solving strategies, and relapse prevention.
An important dimension to consider when studying outcome in eating disorders is underlying personality traits. Bulimic patients are generally characterized by high impulsivity, sensation seeking, and novelty seeking. We found that full-BN and sub-BN shared common psychopathological symptoms and personality traits. In addition, there were significant differences in symptom changes for our primary outcome variables. Concretely, a statistical reduction in binge eating and vomiting frequency was observed for both groups after treatment. In relation to full-BN, this research showed that psycho-education is a useful first intervention for individuals with mild to moderate full BN.
The brief group therapy we applied in our study yielded a low dropout incidence (around 19%). This percentage is lower than those reported in other studies, and it could be related with the motivational work with our patients before initiating therapy (which could improve adherence).
Krug, I., Casasnovas, C., Granero, R., Martínez, C., Jiménez-Murcia, S., Bulik, C., & Fernández-Aranda, F. (2008). Comparison study of full and subthreshold bulimia nervosa: Personality, clinical characteristics, and short-term response to therapy. Psychotherapy Research, 18, 37–47