Human sex differences in d-amphetamine self-administration.
Women and men may respond differently to the effects of stimulants such as amphetamine and cocaine.


OBJECTIVE
In order to assess potential sex differences in the reinforcing effects of d-amphetamine, a retrospective-analysis was conducted on data collected from three studies that employed similar d-amphetamine self-administration procedures and used identical subject-rated drug-effect measures.


METHODS
Data from 10 women and 15 men were included in the analysis. In all studies, participants sampled placebo, low (8-10 mg) or high (16-20 mg) dose oral d-amphetamine. Following sampling sessions, participants worked for capsules containing one eighth of the previously sampled dose on a modified progressive-ratio schedule of reinforcement. We hypothesized that women and men would be differentially sensitive to the reinforcing effects of d-amphetamine. A two-way mixed-model analysis of variance (sex and dose) and planned comparisons were used in the statistical analyses.


RESULTS
The low dose of d-amphetamine functioned as a reinforcer in women, but not men, whereas the high dose of d-amphetamine functioned as a reinforcer in men, but not women. Men self-administered significantly more capsules under the high dose condition than women.


CONCLUSIONS
The results of this study suggest that men are more sensitive to the reinforcing effects of a high dose of d-amphetamine than women. Future research is needed that determines prospectively the reinforcing effects of weight-adjusted doses of d-amphetamine in women and men while controlling for menstrual cycle phase.
Department of Psychology, University of Kentucky, Lexington, KY, USA.
Andrea R
AR
Vansickel
William W
WW
Stoops
Craig R
CR
Rush
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D016739:Behavior, Addictive / Q000523:psychology; D001794:Blood Pressure / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000008:administration & dosage* / Q000494:pharmacology; D003913:Dextroamphetamine / Q000008:administration & dosage* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008597:Menstrual Cycle; D012055:Reinforcement Schedule; D012189:Retrospective Studies; D012646:Self Administration; D012737:Sex Factors; D055815:Young Adult
D000697:Central Nervous System Stimulants; D003913:Dextroamphetamine