clinical safety of treatment will be assessed by notification and with an close-ended inquiry into adverse events together with full physical examination and vital signs measurements. Statistical analyses mean and standard deviation (SD) and comparisons of baseline demographic and clinical characteristics with one-way analysis of variance (ANOVA), chi-square test for categorical variables and mixed-effect analyses of covariance (ANCOVAs) with medication (olanzapine, ketiamine) as between-groups factor and time (1 hour, 2 hours, 4 hours, 6 hours and 12 hours) as a within-group factor. OASS at time zero, OAS at time zero, and presence of excessive sedation will be fixe covariates, and symptom ratings (OASS, OAS and RSS) will be time-varying covariates.