Addiction in its broadest sense can be defined as the habituation to a practice considered harmful. A more narrow definition of the term refers to chronic use of a chemical substance in spite of severe psychosocial consequences. Terms such as "workaholic," "sex addict," and "computer junkie" arose to describe behaviors that have features in common with alcoholism and other substance addictions. The most convincing data supporting a role of genetics in addiction has been collected for alcoholism, although genetics most likely has a role in other forms of addiction.

Definitions

In order to assess alcoholism, or any form of addiction, a clear definition of the condition is necessary. The American Psychiatric Association and the World Health Organization have developed clinical criteria (DSM-IV and ICD10, respectively) that are widely used for the diagnosis of substance-use related disorders. DSM-IV criteria recognizes ten classes of substances (alcohol, amphetamines, cannabis, hallucinogens, inhalants...