Chlorpromazine in chronic schizophrenia: Behavioral dose-response relationships

Fixed daily doses of chlorpromazine (CPZ), in the amounts of 150, 300, and 600 mg were administered orally to chronic schizophrenic inpatients for 24 weeks while psychiatric and ward behavioral responses were monitored at regular intervals. It was found that within the dose range used response could be shown to be dose related, particularly early in the course of treatment (4–12 weeks). CPZ in the amount of 150 nig/day was found to be an effective dose relative to placebo, but was generally less effective than 300 or 600 mg/day. Little difference in clinical response was demonstrable between the 300 and 600 mg doses of CPZ except in the frequency of side effects and possible speed of onset or therapeutic effects, both being greater in the 600 mg group.