Effects of a new slow release formulation of caffeine on EEG, psychomotor and cognitive functions in sleep-deprived subjects

Caffeine is a widely-consumed psychoactive substance whose stimulant effect s on mood, attention and performance are largely recognised. The central ne rvous system pharmacodynamic profile of a single oral dose of a new slow re lease (SR) caffeine formulation (600 mg) was assessed in a randomised, doub le-blind, crossover, placebo-controlled study. Twelve young, health, male, sleep-deprived (for 36 h) subjects were studied using EEG and various measu res of psychomotor and cognitive functions, including critical flicker fusi on (CFF), choice reaction task (CRT), tracking, continuous performance task (CPT), Stroop test, body sway and subjective evaluation (Stanford Sleepine ss Scale). Caffeine significantly (p < 0.05) antagonised the detrimental ef fects of sleep-deprivation on EEG (i.e. produced a significant decrease in delta and theta relative power and a significant increase in alpha and beta (12-40 Hz) relative power) and psychomotor performance (significant increa se in speed of reaction on the CRT and Stroop tests, significant decrease i n body sway, significant increase in accuracy of the CPT and significant re duction in subjective sedation) compared to placebo. The effect peaked 4 h after dosing and was maintained until the end of sleep deprivation (i.e. 24 h after dosing). In conclusion, the present results demonstrate that a sin gle dose of caffeine SR possesses alerting effects which are able to revers e the deleterious effect of 36 h sleep deprivation for at least 24 h. Copyr ight (C) 2000 John Wiley & Sons, Ltd.