The influence of comorbid major depression and substance use disorders on alcohol and drug treatment: results of a national survey.

The co-occurrence of alcohol use disorders, drug use disorders, and major depression has frequently been reported in alcoholic, drug abuse, and psychiatric patient samples (Allen and Francis 1986; Demilio 1989; El-Guebaly 1990; Ross et al. 1988; Rounsaville et al. 1982). Significant associations between substance use disorders and major depression have also been found in general population surveys (Regier et al. 1990; Robins et al. 1988; Weissman and Meyers 1980), but the magnitude is much lower than that reported in clinical samples. This suggests that people with comorbid substance use disorders and major depression may be more likely to seek alcohol or drug treatment than those without such comorbidities. However, to date, no studies have examined the impact of comorbidity on alcohol or drug treatment in the population of greatest clinical and policy relevance, that is, among those persons with an alcohol use disorder or drug use disorder not found in the treated population.