Comorbidity between DSM-IV alcohol and specific drug use disorders in the United States: results from the National Epidemiologic Survey on Alcohol and Related Conditions.

Background: To date, there have been no published data on 12-month comorbidity of DSM-IV alcohol and drug use disorders in the general U.S. population. The purposes of the present study were to examine the prevalence and comorbidity of alcohol and specific drug use disorders, and to identify sociodemographic and psychopathologic correlates and treatment seeking among three groups of respondents: (1) those with alcohol use disorders only; (2) those with drug use disorders only; (3) those with comorbid alcohol and drug use disorders.
Methods: Information on 12-month alcohol and specific drug use disorders in the United States was derived from face-to-face interviews in the National Institute on Alcohol Abuse and Alcoholism's (NIAAA) 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC: n = 43,093).
Results: Prevalences were 7.35% for alcohol use disorders only, 0.90% for drug use disorder only and 1.10% for comorbid alcohol and drug use disorders. Sociodemographic and psychopathologic correlates of these three groups were quite different, with the drug use disorder and comorbid groups significantly more likely to be young, male, never married and of lower socioeconomic status than the alcohol use disorder only group. Associations between current alcohol use disorders and 25 specific drug use disorders were generally positive and statistically significant. The 12-month prevalence of treatment seeking significantly increased from 6.06% for those with an alcohol use disorder only to 15.63% for those with a drug use disorder only, and to 21.76% for those with comorbid alcohol and drug use disorders.
Conclusions: This study provides detailed data on the homotypic comorbidity of alcohol use disorders and 25 different drug use disorders and confirms the high levels of association seen in previous studies based on lifetime measures. Implications of this study are discussed in terms of integrating alcohol and drug treatment services and refining prevention and intervention efforts.