How antipsychotic drugs can cause weight gain

A study of mice has identified a biological mechanism by which certain psychiatric medications cause people to gain weight.

Researchers linked the appetite-increasing effects of three such drugs—the so-called atypical antipsychotics clozapine (Clozaril), olanzapine (Zyprexa), and risperidone (Risperdal)—to their capacity to neutralize the protein histamine, just as the antihistamine drugs that are used to treat allergies do.