Opioids and sleep - a review of literature.

Sleep is an evolutionarily conserved process and is important for rest and recovery of various biological functions. Sleep and alertness alterations, function as contributing/modulatory factors in initiating and maintaining drug and alcohol abuse and as factors that increase the risk for relapse. Opioid dependent individuals frequently complain of sleep problems during withdrawal and abstinence. Sleep disturbances are seen even among patients on opioid substitution therapy (OST). The aim of this review is to present an overview of sleep problems in opioid dependent patients and to delineate factors associated with sleep disturbance.