Admissions to U.K. NHS hospitals with a diagnosis of anorexia have risen by 80% in the last 10 years. Anorexia is notoriously difficult to treat and there is no evidence that antidepressants are effective for it. Antipsychotic drugs are sometimes used to treat anorexia. They reduce agitation and anxiety, increase appetite and lead to weight gain and may tackles some of the psychosis-like characteristics of anorexia. But do they really work?! Researchers from Oxford University reviewed 43 studies into the use of antipsychotics in anorexic patients. The most studied drugs were olanzapine, quetiapine and risperidone. The study concluded that the antipsychotics appeared safe and that there was some evidence that they had a positive effect on depression, anxiety and 'core-eating disordered psychopathology.' However, there was insufficient evidence, for the moment, to say that they actually enhanced weight gain.
McKnight, Rebecca F. and Park, Rebecca J. - Atypical antipsychotics and anorexia nervosa: a review European Eating Disorders Review January-February 2010, 18(1), 10-21