The principal feature of substance withdrawal is development of a substance-specific maladaptive behavioral change, which may have associated physiological and cognitive components, result-ing from the cessation of or reduction in heavy and prolonged substance use. Depression and suicidal ideation are the most serious complications and require individualized assessment and treatment. The syndrome may last up to several days but generally resolves without treatment. The diagnosis of cocaine withdrawal is predicated on the general DSM-IV criteria for sub-stance abuse withdrawal. Specifically it requires the presence of dysphoria and two of the following symptoms devel-oping as short as a few hours after discontinuation of the drug: insomnia, fatigue, increased appetite, psychomotor agitation or retardation, and vivid, unpleasant dreams.