A Multivariant Psychopharmacologic Study in Normals

Abstract

Using a double-blind technique, chlorpromazine (25 mg.), amobarbital (200 mg.), dextroamphetamine (10 mg.), meprobamate (200 mg.), and a placebo were given intramuscularly during 10 weekly 3-hour experimental sessions to 10 fourth-year medical students. The subjects and an experimenter were observed by a psychiatrist and a social scientist. An MMPI and sociometric ratings were obtained on each subject. At 0, 1, 2, and 3 hours each subject took a subjective questionnaire scored for mood, mentation, and sedation; a serial subtraction test; and estimated the drug received. Analysis of variance including the factors drug, experimental session, and subject were performed for the categories on the subjective questionnaire and for the serial subtraction test results. Chlorpromazine, of the drugs in these doses, was clearly the most active. It was sedating, dysphoric, and caused mental clouding. Amobarbital was variable in action and often indistinguishable from placebo. In general it was sedating, caused mental clouding, and little change in mood. Meprobamate showed very little activity. Dextroamphetamine was variable being, in general, slightly alerting, and tending to promote mild euphoria. The principle that quantitative techniques can be applied to the study of subjective effects was borne out. The importance of considering multiple factors in drug action is pointed up. There is evidence that the experimental setting inhibits response. The estimation by the subject of the drug received influences outcome. Membership in a cohesive group facilitated accuracy of drug percept. Social isolation adversely affected correct perception. Individual variation of response was noted. Certain individuals react atypically to a variety of drugs.