RESUMO
The subject of 'drug addiction' is multifaceted and many aspects of it (even some of the definitions) are controversial. Collateral medical problems include the spread of HIV and hepatitis C virus secondary to i.v. drug abuse and effects on prenatal brain development (1). Progress in the understanding of the causes of addictions and its treatment has been impeded by the lack of a unifying biochemical theory. However, recent evidence suggests that some common mechanism might underlie addictions to otherwise apparently unrelated drugs. A major hypothesis has emerged suggesting that the neurotransmitter dopamine (DA) might play a central role in the molecular mechanisms of at least some addictions. If so, it would represent an important target for discovery of effective pharmacotherapy and revolutionize the pharmacist's role in treating addictions. This short overview outlines the status of the theory of a common biochemical mechanism of drug addiction.