Weight gain on antipsychotic medication is associated with sustained use among veterans with schizophrenia.

OBJECTIVE: Continuous antipsychotic treatment is important in schizophrenia, and studies have shown that rates of discontinuation are high. Some studies suggest that weight gain may lead schizophrenic patients to discontinue treatment, whereas other studies show smaller effects of weight gain on medication discontinuation, and some find weight gain associated with symptom improvement. Our retrospective cohort study investigated the effect of weight change on the continued use for 1 year (persistence) of all antipsychotics, then among users of first-generation antipsychotics and second-generation antipsychotics (SGAs), and lastly subgroups of SGAs.

METHODS: We identified 2130 patients with schizophrenia starting an antipsychotic that had not used 1 in the prior year. Using multivariable logistic regression adjusted for demographic and clinical variables, we determined the odds of remaining persistent on medication among patients who either gained weight or did not gain weight in the following year.

RESULTS: For all antipsychotics combined, weight change was not associated with persistence. Among SGAs, weight gain was associated with a 23% increase in the adjusted odds ratio (OR) for persistence (OR, 1.23; 95% confidence interval [CI], 1.00-1.51), whereas there was a nonsignificant decrease in the adjusted odds of persistence among first-generation antipsychotic users (OR, 0.74; 95% CI, 0.43-1.28). When SGAs were divided into subgroups (clozapine/olanzapine, risperidone/quetiapine), both had increases in the likelihood of persistence, but only the association for clozapine/olanzapine was significant at a trend level (adjusted OR, 1.46; 95% CI, 0.99-2.16).

CONCLUSIONS: These findings are supportive of other research that shows weight gain does not invariably lead to medication discontinuation and may be associated with clinical improvement.