Relationships between sleep and addiction: the role of drug-environment conditioning.

Addiction to cocaine and other amphetamine-like psychostimulants is a chronic relapsing disorder characterized by loss of control over drug taking. Sleep disturbance is common among patients in recovery from drug abuse and can precipitate relapse. It has been widely demonstrated that sleep deprivation and psychostimulants share similar neurobiological effects regarding the dopaminergic system. In addition, the persistence of a drug-environment conditioning induced by repeated psychostimulant treatment, which is deeply related to the dopaminergic neurotransmission, is thought to play a key role in the addictive cycle. In this scenario, we hypothesized that sleep deprivation is a potential detrimental factor to the extinction process of previously established drug-environment conditioning. Therefore, sleep deprivation would extend the pairing between the cocaine reinforcing effects and the environmental cues, thereby leading drug abusers to relapse.