Do any of the atypical antipsychotics have more clearly demonstrated antidepressant effects than others?
Quetiapine has shown the best demonstrated antidepressant effect, as noted by two studies in which both 300 mg and 600 mg worked.2,3 In the large, major, pivotal trial, olanzapine also showed effect in bipolar I depression.4 However, the magnitude of that effect was much smaller than that of olanzapine and fluoxetine combination. If there had been a quetiapine-plus-antidepressant arm in the quetiapine studies, the same result may have been observed. In all fairness, quetiapine’s magnitude of effect was somewhat larger than olanzapine’s magnitude of effect. However, there has never been, nor will there ever be, a head-to-head study of those two atypical antipsychotics in bipolar I depression. Although aripiprazole did not show a significant antidepressant effect in the bipolar depression studies,5 the dosing characteristics were not properly determined in advance. As doses were increased in an effort to have partial remitted patients achieve remission, a fair number of people dropped ou
