Substance use and other mental disorders frequently co-occur, complicating diagnosis because many symptoms (e.g., insomnia) are criteria for intoxication, withdrawal syndrome, or other mental disorders. Before DSM-IV, the nonstandardized substance-induced mental disorder criteria had poor reliability and validity. DSM-IV improved this (113) via standardized guidelines to differentiate between “primary” and “substance-induced” mental disorders. In DSM-IV, primary mental disorders were diagnosed if they began prior to substance use or if they persisted for more than 4 weeks after cessation of acute withdrawal or severe intoxication. DSM-IV substance-induced mental disorders were defined as occurring during periods of substance intoxication or withdrawal or remitting within 4 weeks thereafter. The symptoms listed for both the relevant disorder and for substance intoxication or withdrawal were counted toward the substance-induced mental disorder only if they exceeded the expected severity of intoxication or withdrawal. While severe consequences could accompany substance-induced mental disorders (114), remission was expected within days to weeks of abstinence (115–118).
