Olanzapine is an antipsychotic drug, mostly used to treat people suffering from psychosis or schizophrenia. However, there has recently been some research into the use of olanzapine in treating people with anorexia. One of the side effects of olanzapine is weight gain and it is also thought to have some effectiveness in combating obsessional thoughts and depression. People whose anorexia involves restricting their calorie intake tend to have obsessional traits while those who binge and then purge often suffer from dysphoric (depressed) mood. A small study of 34 people with anorexia compared a group taking olanzapine with another group taking a placebo. The group taking olanzapine was found to have a greater rate of increase in weight, an earlier achievement of their target body mass index and a greater rate of decrease of obsessive symptoms. No differences in adverse effects were observed between the two treatment conditions.
Bissada, Hany ... [et al] - Olanzapine in the treatment of low body weight and obsessive thinking in women with anorexia nervosa: a randomized, double-blind, placebo-controlled trial American Journal of Psychiatry October 2008, 165(10), 1281-1288