The importance of the authors' findings hinges on the clinical relevance of the polysomnographic abnormalities that they identified in the cocaine-dependent patients. Do these abnormalities affect important clinical phenomena of the disease, such as euphoria, craving, denial, and hedonic dysregulation (2)? The authors suggest that normalization by an agent like modafinil might actually improve clinical outcome. They cite two references to support this statement (3, 4), which essentially report that normal volunteers are more likely to choose methylphenidate when they are sleepy, suggesting that stimulant reward is enhanced by sleepiness. Along these lines and more to the point, Sofuoglu and colleagues (5) conducted a controlled human laboratory study showing that cocaine users in the state of withdrawal (which includes hypersomnia) reported enhanced euphoria after they smoked a single dose of cocaine. These human laboratory findings suggest that sleepiness might amplify stimulant-induced euphoria, which reinforces stimulant use, but do not specifically demonstrate that sleep deficits "could increase the likelihood for relapse," as stated by Morgan and colleagues (1). Modafinil has been reported to blunt cocaine-induced euphoria in three controlled human laboratory studies (6—8), but positive findings in clinical trials are necessary to establish efficacy.