Zolpidem does not serve as reinforcer in humans subjected to simulated shift work

Zolpidem attenuates shift-change-related sleep and performance disruptions. It is unknown whether these benefits alter the reinforcing effects of the drug during shift work. This study examined zolpidem-related reinforcing effects during simulated shift work. Eleven volunteers (3F, 8M) completed this 16-day within-participant, residential laboratory study. Each day participants were given an opportunity to self-administer oral zolpidem (10 mg) or receive a $1 voucher immediately following a 9-h work period and immediately before going to bed. Participants worked under two shift conditions: (1) during the night shift, participants completed computerized task batteries from 00:30 to 09:30 h and went to bed at 16:00 h and (2) during the day shift, participants completed task batteries from 08:30 to 17:30 h and went to bed at 24:00 h. Shift conditions alternated three times during the study. Despite the fact that sleep, psychomotor performance, and some ratings of mood were disrupted during night-shift work, there was no significant effect of shift on choice to take zolpidem. Overall, participants selected markedly fewer zolpidem doses than monetary vouchers (17% versus 83%). Thus, zolpidem did not serve as a reinforcer even when sleep was disrupted. These data are consistent with previous reports indicating that sedatives produce limited reinforcing effects in individuals without a history of drug abuse.