Insomnia is diagnostically characterized by difficulty in initiating and maintaining sleep, and is usually accompanied by subjective complaints of non- refreshing sleep and behavioral impairments during the day. There may be evidence of increased heart rate and sympathetic tone (Bonnet and Arand, 1995), increased cerebral glucose metabolism during both wake and sleep states (Nofzinger et al., 2004), and activation of the hypothalamic-pituitary-adrenal

Objective: To evaluate next-day driving ability, as assessed by brake reaction time (BRT), and cognitive/psychomotor function following nighttime administration of 3 mg eszopiclone.

Methods: Two randomized, double-blind, placebo-controlled, cross-over studies were performed in healthy volunteers (n 1⁄4 32) and patients with primary insomnia (n 1⁄4 32). Study participants received nighttime dosing of 3 mg eszopiclone or placebo. BRT and a psychometric test battery were used to assess the next-day effects of eszopiclone treatment