22 - Cocaine

Abstract

Cocaine dependence is a chronic disorder characterized by compulsive drug-seeking, frequent relapses, and continued drug use despite negative consequences. Although the molecular biological mechanisms of many aspects of cocaine dependence are still being elucidated, work in many labs over the past several years has led to the development of heuristic models whereby repeated exposure to cocaine results in long-term neuroadaptations in several areas of the brain, particularly those related to processing of reward-related information, emotion and stress regulation, and executive control of behavior. These neuroadaptations, on the one hand, allow the brain to function relatively normally under conditions of intoxication, but, on the other hand, result in significant functional alterations in dopaminergic signalling pathways, thereby evoking powerful physiological and psychological symptoms under conditions of challenge and arousal and when cocaine is withdrawn. Neuroadaptations that occur as the result of repeated cocaine exposure can be extremely long lasting even after periods of extended abstinence. As a result, cocaine addiction is characterized by repeated episodes of bingeing, withdrawal, recovery, and relapse. Furthermore, some of these neuroadaptations are different in men and women and are also affected by age at onset of regular cocaine use.