SELF-MONITORING COGNITIVE PERFORMANCE DURING SLEEP-DEPRIVATION - EFFECTS OF MODAFINIL, D-AMPHETAMINE AND PLACEBO

Self-monitoring refers to the ability to assess accurately one's own p erformance in a specific environment. The present study investigated t he effects of the stimulating drugs modafinil (300 mg) and d-amphetami ne (20 mg) on the ability to self-monitor cognitive performance during 64 h of sleep deprivation (SD) and sustained mental work. Two cogniti ve tasks were investigated: a visual (perceptual) judgment task and a complex mental addition task. Subjects in the placebo condition displa yed marked circadian and SD effects on cognitive task performance but their self-monitoring was substantively undisturbed by SD. Subjects pe rforming under the influence of d-amphetamine likewise displayed highl y proficient self-monitoring throughout the SD period. In contrast, mo dafinil had a disruptive effect on self-monitoring, inducing a reliabl e 'overconfidence' effect (i.e. an overestimation of actual cognitive performance), which was particularly marked 2-4 h post-dose. Although modafinil has proven to be a safe and effective countermeasure to the effects of extensive SD on cognitive task performance, we encourage a more comprehensive understanding of the relation between its subjectiv e and performance enhancing effects before the drug is recommended as a viable fatigue countermeasure.