Olanzapine versus placebo in acute mania: treatment responses in subgroups

Two double-blind, placebo-controlled trials of olanzapine in acute mania showed significant overall antimanic efficacy, based on reductions in mania ratings. Their subject-level data were pooled to increase statistical power to test for differences in treatment responses among 10 subgroup pairs of interest using generalized estimating equations methods. Similar drug/placebo superiority and responsiveness to olanzapine was found in men versus women, psychotic versus nonpsychotic subjects, and those presenting in mania versus mixed states, and responses were independent of onset age, current age, or prior illness based on episodes, hospitalizations, recent rapid cycling, lifetime substance use, or previous antipsychotic treatment. Olanzapine and placebo responses paralleled closely (r(s) = 0.73). Patients were relatively more responsive to olanzapine who were younger at illness onset, lacked prior substance abuse, and had not previously received antipsychotic treatment (efficacy ratios 1.5-1.7, all P < 0.01). These well-powered comparisons of subgroups of interest indicate broad efficacy of olanzapine in the treatment of acute mania.