EFFECT OF SETTING ON THE REINFORCING AND SUBJECTIVE EFFECTS OF ETHANOL IN SOCIAL DRINKERS

The reinforcing and subjective effects of two doses of ethanol [0.5 g/ kg (LOW) and 0.8 g/kg (HIGH)] were evaluated under two conditions, a s ocial condition (SOC), in which subjects were tested with two Or three other subjects, and a socially isolated condition (ISO), in which sub jects were tested alone. Forty-one social drinkers participated in a d ouble-blind, seven-session choice procedure. Subjects were randomly as signed to one of four experimental groups: SOC-LOW, SOC-HIGH, ISO-LOW, or ISO-HIGH. On the first four sessions, subjects sampled ethanol (0. 5 or 0.8 g/kg) on two occasions and placebo on the other two occasions . On the three remaining sessions, subjects selected and consumed whic hever of the two previously sampled substances they preferred. The num ber of sessions on which they chose ethanol was the primary measure of the reinforcing effects of ethanol. Standardized self-report question naires and a psychomotor test were used to measure subjective and obje ctive drug effects. Subjects in the SOC condition chose ethanol over p lacebo on significantly more sessions than subjects in the ISO conditi on. Ethanol produced positive subjective effects (e.g., increased rati ngs of drug liking and euphoria) for subjects in the SOC condition, bu t for subjects in the ISO condition, it produced apparently negative e ffects (e.g., increased ratings of dysphoria). These results extend pr evious reports that the behavioral effects of ethanol depend upon the social condition in which it is consumed.