Abstract
Individual differences that may contribute to vulnerability to abuse drugs have been identified. Sensation-seeking status has been shown to influence both vulnerability to drug use and response to acute drug administration. The purpose of the present experiment was to examine the reinforcing effects of d-amphetamine in high and low sensation-seeking subjects using a modified progressive-ratio procedure. A battery of subject-rated, performance, and cardiovascular measures was also included to better characterize the effects of d-amphetamine in these groups. Ten high sensation seekers and ten low sensation seekers that were matched for education, age, drug use, height, and weight, first sampled doses of d-amphetamine (0, 8, and 16 mg). In subsequent sessions, subjects were offered the opportunity to work for the sampled dose on a modified progressive-ratio procedure. d-Amphetamine functioned as a reinforcer and produced prototypical stimulant-like effects (e.g., increased subject-ratings of Like Drug, enhanced performance, and increased heart rate). High sensation seekers were more sensitive than low sensation seekers to the reinforcing and some of the subject-rated effects of d-amphetamine. The results of the present experiment extend those of previous findings by demonstrating that the reinforcing effects of d-amphetamine vary as a function of the biologically based sensation-seeking personality trait. These results suggest that increased stimulant drug use and abuse among high sensation seekers may be related, in part, to increased sensitivity to the reinforcing effects of stimulants among these individuals.