The efficacy of olanzapine in the reduction of and maintenance of the reduction of the manifestations of schizophrenia and related psychotic disorders was established in 3, well-controlled clinical trials of psychotic inpatients who, at entry met the DSM-III-R criteria for schizophrenia (most with a course at entry of "chronic with acute exacerbation") and 1 well-controlled clinical trial of psychotic inpatients and outpatients who, at entry, met the DSM-III-R criteria for schizophrenia, schizophreniform disorder, or schizoaffective disorder. The results of one such trial is as follows:
(1) A 6-week placebo-controlled trial (N=335) compared 3 fixed dosage ranges of olanzapine (5 ± 2.5, 10 ± 2.5, and 15 ± 2.5 mg/day QD), 1 dosage range of haloperidol (15 ± 5 mg/day on a BID schedule), and placebo. The 2 higher dosage ranges of olanzapine were statistically significantly superior to placebo on the Brief Psychiatric Rating Scale (BPRS) total, the Clinical Global Impressions - Severity of Illness (CGI-S) scale, and the BPRS positive psychosis cluster. The highest dosage range of olanzapine was statistically significantly superior to placebo and to haloperidol on the Scale for the Assessment of Negative Symptoms (SANS). Efficacy of olanzapine generally increased with dose. The 5 ± 2.5 mg/day dosage range of olanzapine was numerically but not statistically, significantly superior to placebo on BPRS total and other assessments of over all psychopathology.
While the efficacy of olanzapine at a dose of 5 mg/day was not statistically superior to placebo (see (1)), some individual patients receiving this dose had a good acute response, and were well maintained during a one year extension phase.