 A relatively new treatment for the excessive daytime sleepiness EDS associated with inadequate sleep is the drug modafinil. Modafinil decreases subjective reports and objective measures of daytime sleepiness under conditions of sleep restriction, while enhancing cognitive performance. At the same time, sleep quality does not appear to be affected significantly. Interestingly, recent clinical trials in cocaine-dependent populations suggest that modafinil reduces the relapse to cocaine use, by unknown mechanisms. 