 A randomised controlled, double blind study is intended. During a 6 weeks treatment trial two groups of patients will be basically treated with olanzapine starting with 5 mg after one week with an optional, BPRS-controlled step by step increase of about 2,5 mg each following week. Patients will receive a placebo controlled adjunctive therapy with OXC 1800 mgday. After the initial lead-in of OXC within 7 days allowing lorazepam as comedication, treatment with olanzapine will be started. Based on biometric calculations, a drop out adjusted sample size of 222 inpatients will be necessary 