Disrupted Sleep-Wake Rhythm and Performance: Advantages of Modafinil

Abstract

The pharmacological approach to the management of vigilance during sus- tained operations is a substantial aspect of circadian sleep-wake rhythm con- trol. The use of psychotropic drugs has many advantages but also faces limits and constraints. The synthesis of new awakening compounds called eugregoric may completely change our approach to psychostimulants. We review general pharmacological properties and current knowledge for one of these molecules (modafinil) and report results of psychomotor tests performed during a 60-hr sleep deprivation experiment conducted on eight healthy military volunteers. The seven tests included a reaction time task, a mathematical processing task, a memory search task, a spatial processing task, an unstable tracking task, a grammatical reasoning task, and a dual task combining unstable tracking with concurrent memory search. With the administration of modafinil in doses of 200 mg three times per day, the overall performance remained identical to that obtained during control trials without sleep deprivation. Performance after modafinil remained constant except for cyclic variations due to the influence of the endogenous circadian rhythm. After the administration of a placebo, perfor- mance decreased more or less regularly, depending on tasks, as a function of sleep deprivation and circadian fluctuations. The efficacy of this substance and the observed absence of side effects make eugregoric rnolecules in general, and modafinil in particular, valuable pharmacological tools and promising medi- cines for military and emergency health care applications during extended duty cycles and for therapeutic purposes.