Addiction

Abstract

Addiction includes compulsive seeking of drugs of abuse. These drugs produce positive emotional states following intake, but may lead to negative feelings in their absence. Multiple approaches will be necessary to understand addiction. However, we can assume that part of our understanding will come from exploration of molecules and brain circuitry that predispose to addictive behaviour, and change after drug experimentation. We examine these ideas, focusing on the ‘reward pathway’ in the brain. Addiction studies, in addition to combating a major scourge of society, offer an opportunity to understand mechanisms of neural plasticity important to the brain's ability to learn.

Key Concepts

• Addiction refers to compulsive use of a class of drugs known as ‘drugs of abuse’.

• The ‘reward pathway’ in the brain is a major target of drugs of abuse.

• The initial positive feelings generated by these drugs can diminish with use, and may reduce the reward derived from previously rewarding nondrug experiences.

• Addiction can be understood in terms of molecules and brain circuits that may differ in individuals and predispose to addictive behaviour, and may change as a result of drug experimentation, leading to compulsive drug use.

• Many of the important issues of neuroscience can be examined within the context of addiction. These include the brain mechanisms of reward, genetic predisposition to behaviours, and neuronal plasticity.