FACTORS INFLUENCING THE REINFORCING AND SUBJECTIVE EFFECTS OF D-AMPHETAMINE IN HUMANS

The reinforcing and subjective effects of oral d-amphetamine (AMP) wer e studied in a group of non-drug-abusing adults (16 males, 13 females) . A discrete-trial choice procedure was used to assess the reinforcing effects of a single dose of AMP (range 7.5-20 mg across subjects). A number of factors (gender, current and past drug use, personality, mot or activity, and baseline mood state and psychophysiological and senso ry indices of arousal) were examined in an attempt to explain both wit hin- and between- subject variability in response to AMP. Of the 29 su bjects, 11 chose AMP on either two or three out of a possible three oc casions. Cigarette smokers reported stronger aversive responses to AMP and chose the drug significantly less often than non-smokers. Subject s with a history of non-medical stimulant use reported less subjective response to AMP than subjects without such history. Within-subject va riability in AMP choice was related to variability in subjective respo nse to the drug across choice trials, as well as to variability in bas eline mood: AMP was more likely to be chosen when subjects were more a roused and in a more positive mood at the time of the choice. These re sults provide new information regarding factors that may be relevant i n determining individual differences in vulnerability to abuse of psyc homotor stimulants.