The Neurobiology of Addiction

101 Addiction can be defined from a behavioral viewpoint as repeated self-administration of alcohol or other drugs (AOD’s) despite knowledge of adverse medical and social consequences and attempts to abstain from AOD use. Typically, an addicted person’s daily activities are centered on obtaining and consuming the drug at the expense of social and occupational commitments. Many factors contribute to the development of addiction. A person’s initial decision to use a drug is influenced by genetic, psychosocial, and environmental factors. Once it has entered the body, however, the drug can promote continued drug-seeking behavior by acting directly on the brain. Research over the past two decades has increased our understanding of the neural processes that underlie drugseeking behavior. This article summarizes some of the molecular and cellular events in the brain that appear to be associated with addiction. The article first discusses some observable manifestations of addiction and basic mechanisms involved in initiating and maintaining addictive behavior. The hypothesized roles of various chemical communication systems of the brain (i.e., neurotransmitters and receptors) are explored, followed by a discussion of the interactions between these systems within brain regions thought to be involved in addiction. Finally, the article discusses the suggested role of an integrated system of neural connections involving several adjacent brain regions. This article is not an exhaustive overview, but a sampling of some topics of interest to researchers studying addiction neurobiology. The Neurobiology of Addiction