Polydrug dependence and psychiatric comorbidity among heroin injectors.

The prevalence of diagnoses of substance dependence, anxiety disorders and depressive disorders were estimated in a sample of 222 heroin injectors, using the Composite International Diagnostic Interview. Subjects had a median of three lifetime substance diagnoses and two current diagnoses. A total of 60% met the criteria for a lifetime anxiety disorder, and 51% had a current anxiety disorder. A depressive disorder was diagnosed in 41% of subjects, with 30% having a current diagnosis. There were significant positive correlations between the number of lifetime drug dependence diagnoses and the number of lifetime anxiety and affective disorders (r = 0.41), and the number of current drug dependence diagnoses and the number of current comorbid diagnoses (r = 0.32). After controlling for other variables, the only significant independent predictor of the number of lifetime and current dependence diagnoses was the number of comorbid diagnoses.