Abstract

If one believes that the brain is, in some as yet unspecified way, the organ of mind and behaviour, then all human behaviour has a neurobiological basis. Neuroscience research over the past several decades has provided more specific reasons for believing that many addictive phenomena have a neurobiological basis. The major psychoactive drugs of dependence have been shown to act on neurotransmitter systems in the brain (Nutt 1997; Koob 2000); common neurochemical mechanisms underlie many of the rewarding effects of these drugs and the phenomena of tolerance and withdrawal symptoms (Hyman & Malenka 2001; Koob 2000), and there is evidence for a genetic vulnerability to addiction (Nestler 2001; Uhl 1999) that is mediated by genes that regulate the metabolism of psychoactive drugs and the brain neurotransmitter systems on which they act (Uhl 1999).