Amphetamine pretreatment accelerates the subsequent escalation of cocaine self-administration behavior.

It has been proposed that some neuroadaptations that underlie behavioral sensitization may play a role in the development and persistence of addiction. However, whether or not sensitization facilitates the development of symptoms specific to addiction, such as the escalation of drug intake, is not known. We examined, therefore, the effect of pretreatment with a sensitizing regimen of amphetamine on the escalation of subsequent drug intake in rats given the opportunity to self-administer cocaine. Amphetamine pretreatment produced psychomotor sensitization and also accelerated the subsequent escalation of cocaine intake. This suggests that the neural circuits that are altered as a consequence of repeated amphetamine treatment, and the induction of sensitization, may overlap with those responsible for the development of some addiction-like behaviors.