To date, there are no evidence-based pharmacotherapies for treating co-occurring anorexia nervosa and AOD use. Guidelines suggest that pharmacotherapy alone should not be the primary treatment for single disorder anorexia nervosa, and there is little consistency between guidelines with regard to recommendations relating to specific medications [870, 1428, 1434].
Although atypical antipsychotics and SSRIs (olanzapine and fluoxetine in particular) have been used in clinical settings, research indicates that there is no conclusive evidence of any effect on the primary psychological features of anorexia nervosa or weight gain, but they may assist in treating other psychological symptoms (e.g., depression) that may co-occur with anorexia nervosa [1414, 1429, 1447, 1448]. Nonetheless, it has been suggested that olanzapine is currently the best pharmacotherapy available for anorexia nervosa, particularly for those who cannot access other intensive treatments [1449, 1450]. A comprehensive review of pharmacotherapy for single disorder anorexia nervosa found that olanzapine increased weight gain and improved depression, anxiety, aggression and obsessive-compulsiveness [1451]; however, the evidence remains weak and there is the possibility of adverse side effects [870].