Persistent Effect of Chlorpromazine on Extinction of an Avoidance Response

Abstract

Clinical experience with the ataractic agents has established their value in the reduction of manifest anxiety and the consequent management of the agitated patient. The role of these agents in the production of permanent therapeutic effects is still to be established. The present experimental study suggests that the ataractic agents may be of value in the production of such therapeutic responses when utilized as adjuncts to psychotherapeutic procedures. During the course of experimental studies of the behavioral effects of tranquilizing agents, it was observed that the injection of chlorpromazine²in the amount of 1.25 mg. per kilogram of body weight almost completely suppressed avoidance conditioned responses in the rat for a period of several hours. When the animals were retested 24 hours after the administration of the agent, the avoidance behavior was fully recovered. Even when the drug was administered on two or three occasions during extinction testing, the