[Neural circuits and neurotransmitters involved in the effects of psychoactive drugs - State of the art with a focus on cocaine].

Addiction is a chronic disease that has serious consequences, both in terms of public health and economy. Clear characteristics distinguish recreational and controlled use from addiction. Thus, today, addiction includes the notions of compulsive drug use, associated with a loss of control over consumption, leading to craving. When consumption is stopped, withdrawal symptoms may emerge: a negative emotional state, cognitive problems and physical symptoms with some products (alcohol and opiates, for example). Relapse episodes may occur during this withdrawal period, countering the negative effects of withdrawal. Relapse episodes can also be observed after long periods of abstinence. They can be precipitated by re-exposure to the context in which the drugs were taken, or by stress. Regardless of the stage of addiction (e.g., development of the addictive behavior, or relapse) changes in brain function and structure can be observed. Some brain structures are therefore modified, such as the prefrontal cortex, where several neuroadaptations have been identified. Some of these changes are described in this paper.