Does olanzapine have antidepressant properties? A retrospective preliminary study

Objective: Mood-stabilizing agents are ideally conceptualized as possessing antimanic and antidepressant properties. While research on olanzapine's antimanic effects is growing, data on its possible antidepressant properties are limited. We sought to determine if olanzapine is effective in the add-on treatment of major affective disorders, particularly depressive symptoms, in a naturalistic setting. Methods: All charts of patients meeting DSM-IV criteria for bipolar disorder or unipolar major depressive disorder treated with olanzapine in a private psychiatric practice were reviewed and clinical response was assessed retrospectively using the Clinical Global Impression Scale for Improvement (CGI-I). Results: Olanzapine was moderately effective in 6/10 (60%) patients. Side-effects were present in 8/10 (80%), most commonly weight gain. Conclusions: Olanzapine appears to be moderately effective in open add-on treatment in patients with mainly depressive symptoms. Accumulating evidence suggests that olanzapine, and atypical antipsychotics in general, possess mild to moderate adjunctive antidepressant properties.