Randomized, double-blind trial of olanzapine versus placebo in patients prodromally symptomatic for psychosis

Objective: This study assessed the efficacy of olanzapine in delaying or preventing conversion to psychosis and reducing symptoms in people with prodromal symptoms of schizophrenia. Method: This randomized trial occurred at four North American clinics in the Prevention Through Risk Identification, Management, and Education project. Outpatients received olanzapine (5–15 mg/day, N=31) or placebo (N=29) during a 1-year double-blind treatment period and no treatment during a 1-year follow-up period. Efficacy measures included the conversion-to-psychosis rate and Scale of Prodromal Symptoms scores. Results: During the treatment year, 16.1% of olanzapine patients and 37.9% of placebo patients experienced a conversion to psychosis, a nearly significant difference. The hazard of conversion among placebo patients was about 2.5 times that among olanzapine-treated patients, which also approached significance. In the follow-up year, the conversion rate did not differ significantly between groups. During treatment, th...