The World Health Organization sponsored study group on anorexia nervosa (AN): basic mechanisms, clinical approaches and treatment

Anorexia nervosa is a severe psychiatric disorder that leads to a significant mortality rate (up to 20% in some series) (Schwartz and Thompson, 1981). Moreover, the morbidity is substantial as it affects individuals during important formative years, having a negative impact on such outcomes as education, career training, and reproduction. Several epidemiological studies have reported an increase in the incidence of anorexia nervosa in the last few decades. Dieting is the major risk factor for anorexia nervosa. As the rate of dieting increases among the population at risk, namely, young women, it becomes important to accurately diagnose and treat anorexia nervosa. Anorexia nervosa is further complicated by co-morbidity with other psychiatric disorders, including depression, anxiety, and substance dependence (Hahni et al., 1991). Even though biological, behavioral, and psychological treatments can be effective, up to 50% of patients have persistent symptoms (Yales, 1990). There is no specific intervention that directly addresses pathogenetic mechanisms, because anorexia nervosa is a disorder of unknown cause. On September 27-29, 1993, the study group on anorexia nervosa (AN), sponsored by the World Health