Restoration of risk-propensity during sleep deprivation: caffeine, dextroamphetamine, and modafinil.

INTRODUCTION

Sleep deprivation alters risk-related judgments, decision-making, and behavioral control. Stimulant medications are used to restore cognitive performance, but their effects on risk-taking and judgment in sleep-deprived subjects have not been explored.

METHODS

There were 54 healthy adults (29 men, 25 women; age range 18 to 36) who completed a test of cognitive ability and daily measures of risk-taking propensity, including the Brief Sensation Seeking Scale (BSSS), Evaluation of Risks (EVAR) scale, and the Balloon Analog RiskTask (BART). Following 44 h of continuous wakefulness, participants ingested caffeine 600 mg (N = 12), dextroamphetamine 20 mg (N = 16), modafinil 400 mg (N = 12), or a placebo (N = 14) in a double blind manner, and completed risk-taking measures 2 h later (i.e., 0535).

RESULTS

Relative to rested baseline, the placebo group showed a decline in risk-taking as measured by the BSSS (16% decline), EVAR Danger Seeking (32% decline) and Energy (22% decline), and BART (32% decline), consistent with previous reports of the effects of sleep deprivation. Comparisons among drug conditions showed that dextroamphetamine restored risk-taking propensity and risky behavior to baseline levels, an effect that was significantly greater than placebo or caffeine for several indices of risk-taking, but which did not differ from modafinil. Cognitive ability was significantly correlated with changes on some risk-taking indices following stimulant administration.

CONCLUSIONS

Stimulant medications, particularly dextroamphetamine, sustained risk-related attitudes and behavior during continuous wakefulness. The extent to which stimulants restore other aspects of judgment during sleep loss remains to be determined.