A neurochemical basis for alcohol and other drug addiction.

There are major clinical observations in alcohol and other drug addicts and neurochemical studies in animals and humans that support the hypothesis for a common neurochemical basis for alcohol and other drug addiction. The common occurrence of concurrent alcohol and multiple drug dependence in clinical and general populations, family history and genetic studies, and basic and clinical research in the neurochemistry of addictive behavior provide evidence for a common genealogical vulnerability to combined alcohol and other drug addiction. Clinical neurochemical models for addictive behaviors can be derived from neurochemical pathways for the initiation and sustenance of addictive disorders. The role of tolerance and dependence is not specific to addiction but indicates a homeostatic response of the brain to the presence of a foreign substance. Animal and human studies are analyzed for clinical synthesis of a neurochemical basis for addictive disorders.