Prevalence of substance abuse in a psychiatric evaluation unit.

The prevalence of substance abuse and psychiatric illness was studied in a Psychiatric Evaluations Unit. Twenty-six percent of the subjects received a psychiatric diagnosis only with no concomitant substance use disorder. Thirty-four percent were diagnosed with a substance use disorder but with no other psychiatric disorders. Thirty-nine percent of the subjects had a history of both psychiatric and substance use disorder; 62% of these substance abusers with a psychiatric illness reported using drugs (including alcohol) the week before the interview; 56% used illicit drugs while 44% used alcohol only. Differences among substance abusers with a psychiatric illness, those with a substance abuse diagnosis alone, and those with a psychiatric diagnosis alone are presented.