When applied to psychoactive substance use, the term refers to a powerful urge-attributed to internal feelings rather than external influences- to take the substance (or substances} in question. The substance user may recognize the urge as detrimental to well-being and may have a conscious intent to refrain. These feelings are less characteristic of alcohol and drug dependence than of the psychiatric syndrome of obsessive-compulsive disorder.
WHO Lexicon of alcohol and drug terms