Effect of modafinil on simulated driving performance

Modafinil (2-[(diphenylmethyl)sulfinyl]acetamide, Modavigil®) is a novel stimulant medication shown to improve alertness, cognitive performance and subjective mood. It is thought to be a superior alternative to amphetamines; with its neuropsychological profile and resulting behavioural effects suggesting it is functionally distinct from conventional stimulants, such as dexamphetamine. The current study investigated acute driving-related cognitive skills and simulated driving performance following a 200mg single dose of modafinil in well rested individuals, using measures of driving performance that have been demonstrated to be negatively affected by dexamphetamine. Twenty participants completed the double-blinded placebo-controlled crossover study, completing a battery of cognitive tasks (Occupational Safety Performance Assessment Technology, reaction time index, stop signal task, rapid visual information processing) and a simulated driving scenario at baseline and at 3 hours post drug administration (peak drug level). No deleterious effects of modafinil were found, which is in contrast to dexamphetamine use on comparable tasks. Subjective levels of alertness were higher at peak modafinil compared to placebo; modafinil lead to faster stop signal reaction time on the stop signal task; less lateral lane deviation and a trend towards fewer centre line crossings were apparent during simulated driving. The findings of the current study indicated that modafinil selectively improves neuropsychological task performance in a functionally different way compared to conventional stimulants, specifically dexamphetamine. These differences in cognitive and behavioural performance may be attributable to the differing neurochemical profile of these drugs, and demonstrate a reduced risk to road safety for modafinil in comparison to existing stimulant medications