Objective. To evaluate the association between past 30-day use of alcohol, marijuana, and other illicit drugs and past year unmet need for and use of mental health care.
Data Source. A subsample of 18,849 respondents from the 2001 National Household Survey on Drug Abuse and the 2002 National Survey on Drug Use and Health. Subjects were between the ages of 18 and 65 years and had least one past year mental disorder symptom and no past year substance dependency.
Study Design. Logistic regressions of past 30-day substance use on past 12-month unmet need for mental health care and past 12-month use of mental health services controlling for clinical and sociodemographic characteristics. Predicted probabilities and corresponding standard errors are reported.
Principal Findings. Use of illicit drugs other than marijuana increased with unmet need for mental health care (4.4 versus 3.2 percent, p=.046) but was not reduced with mental health-care use. Heavy alcohol use was not associated with increased unmet need for mental health care, but was higher among individuals with no mental health care use (4.4 percent versus 2.7 percent, p<.001). By contrast, marijuana use did not appear associated with either unmet need or mental health care use.
Conclusions. Substance use varies with past year unmet need for mental health care and mental health care use in ways consistent with the self-medication hypothesis. Results suggest that timely screening and treatment of mental health problems may prevent the development of substance-use disorders among those with mental disorders. Further research should identify subgroups of individuals for whom timely and appropriate mental health treatment would prevent the development of substance-use disorders.