Self-monitoring cognitive performance during sleep deprivation: effects of modafinil, d-amphetamine and placebo

J Sleep Res. 1997 Jun;6(2):84-91. doi: 10.1111/j.1365-2869.1997.00032.x.


Self-monitoring refers to the ability to assess accurately one's own performance in a specific environment. The present study investigated the effects of the stimulating drugs modafinil (300 mg) and d-amphetamine (20 mg) on the ability to self-monitor cognitive performance during 64 h of sleep deprivation (SD) and sustained mental work. Two cognitive tasks were investigated: a visual (perceptual) judgement task and a complex mental addition task. Subjects in the placebo condition displayed marked circadian and SD effects on cognitive task performance but their self-monitoring was substantively undisturbed by SD. Subjects performing under the influence of d-amphetamine likewise displayed highly proficient self-monitoring throughout the SD period. In contrast, modafinil had a disruptive effect on self-monitoring, inducing a reliable '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 subjective and performance enhancing effects before the drug is recommended as a viable fatigue countermeasure.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Benzhydryl Compounds / pharmacology*
  • Central Nervous System Stimulants / pharmacology*
  • Cognition / drug effects*
  • Dextroamphetamine / pharmacology*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Modafinil
  • Placebos
  • Sleep Deprivation*


  • Benzhydryl Compounds
  • Central Nervous System Stimulants
  • Placebos
  • Modafinil
  • Dextroamphetamine