Sleep disorders have been reported in approximately 80% of Tourette's syndrome (TS) patients. Sleep studies in TS patients have demonstrated a 30% reduction in delta-sleep (slow-wave sleep) in nontreated subjects, decreased percentage of REM-sleep and the presence of tics during sleep. A subgroup of young TS patients was reported to have an increased percentage of delta sleep. Although these findings were initially thought to result from deranged dopaminergic and serotoninergic functions in TS, we suggest that abnormalities of hypothalamic-mediated control mechanisms involving the intrinsic opioids may also account for the observed derangements in sleep-wave patterns in TS patients. Evidence for impaired hypothalamic regulation in TS patients includes our preliminary observations of abnormal growth-hormone release to administration of the opiate antagonist naloxone in TS. These data further suggest an interrelationship of neurochemical mechanisms involving opioid-mediated hyperactivity, slow-wave sleep and growth hormone at the level of the hypothalamus.