Caffeine effects on risky decision making after 75 hours of sleep deprivation.
BACKGROUND
Recent research indicates that sleep deprivation impairs decision making. However, it is unknown to what extent such deficits are exacerbated in a dose-response manner by increasing levels of sleepiness, and the extent to which such sleep-loss-induced deficits can be reversed by caffeine.


METHODS
At three time points, 26 healthy subjects completed alternate forms of the Iowa Gambling Task (IGT): rested baseline, 51 h awake, and 75 h awake. Every 2 h each night, 12 volunteers also received 4 200-mg doses of caffeine, with the last dose occurring 3 h prior to the IGT.


RESULTS
At baseline, volunteers readily learned to avoid disadvantageous high-risk card decks while progressively choosing more frequently from advantageous low-risk card decks. When sleep deprived, however, these same subjects showed impaired performance, choosing more frequently from the disadvantageous high-risk card decks, particularly during the latter half of the game. Contrary to expectations, the severity of performance impairment did not increase significantly from 51 to 75 h of wakefulness, and caffeine had no significant effects on IGT performance during sleep deprivation.


CONCLUSIONS
As a provisional extension of our previous study, these preliminary findings further suggest that the ability to integrate emotion with cognition to guide decision making, a capacity believed to be mediated by the ventromedial prefrontal cortex, may be particularly vulnerable to sleep loss. Moreover, these capacities may not be significantly improved by moderate doses of caffeine, suggesting that they may function separately from simple arousal and alertness systems.
Killgore
William D S
WD
Department of Behavioral Biology, Walter Reed Army Institute of Research (WRAIR), 503 Robert Grant Avenue, Silver Spring, MD 20910, USA. william.d.killgore@us.army.mil
Lipizzi
Erica L
EL
Kamimori
Gary H
GH
Balkin
Thomas J
TJ
D000328:Adult; D000704:Analysis of Variance; D001143:Arousal / Q000502:physiology; D002110:Caffeine / Q000494:pharmacology*; D003072:Cognition Disorders / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D003657:Decision Making / Q000187:drug effects*; D005260:Female; D005715:Gambling; D006801:Humans; D008297:Male; D009042:Motivation; D009483:Neuropsychological Tests; D011597:Psychomotor Performance; D012309:Risk-Taking; D012892:Sleep Deprivation / Q000150:complications / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome
D002110:Caffeine