As the term "addiction" has come to be used in medicine less often and with a more restricted meaning, "dependence" has taken its place in many official formulations.
Addiction is a condition that results when a person ingests a substance which may include opiates, alcohol or cocaine or engages in an activity such as gambling that can be pleasurable but the continued use of which becomes compulsive and interferes with ordinary life responsibilities, such as work or relationships, even health. Users may not be aware that their behavior is out of control and causing problems for themselves and others.
In 1969 WHO's Expert Committee on Drug Dependence defined it as follows: "A state, psychic and sometimes also physical, resulting from the interaction between a living organism and a drug, characterised by behavioral and other responses that always include a compulsion to take the drug on a continuous or periodic basis in order to experience its psychic effects, and sometimes to avoid the discomfort of its absence. Tolerance may or may not be present" (World Health Organization 1969, p. 61).
In 1993 ‘dependence’ was defined in even vaguer terms: ‘A cluster of physiological, behavioural and cognitive phenomena of variable intensity, in which the use of a psychoactive drug (or drugs) takes on a high priority.
The necessary descriptive characteristics are a preoccupation with a desire to obtain and take the drug and persistent drug-seeking behaviour .The existence of a state of dependence is not necessarily a generic term of addiction.
However, most addictive behavior is not related to either physical tolerance or exposure to cues. People compulsively use drugs, or gamble or shop, nearly always in reaction to being emotionally stressed, whether or not they have a physical addiction. Since these psychologically based addictions are not based on drug or brain effects,