Although atypical antipsychotics can cause weight gain,
this effect is independent from the development of diabetes;
the exact mechanism by which atypical agents might
cause diabetes is unknown.22,23 In one retrospective cohort
study of 3,015 patients comparing olanzapine (Zyprexa)
with risperidone (Risperdal), both were associated with
gaining weight in the first year but only olanzapine was
shown to be associated with the development of diabetes.23
The diabetogenic potential of antipsychotics appears to be
reversible if the medication is discontinued.