The purpose of this application is to enhance our understanding of the pathways into drug and alcohol services utilized by individuals with drug and alcohol disorders. Of public health concern is the lack of services utilization among individuals with clinically defined need for services (substance abuse or dependence), which we conceptualize as unmet need. While research has identified a range of effective services for treating alcohol and drug disorders, both in primary care and specialty care, few individuals with these disorders receive services. We conceptualize substance use services broadly, including primary care, specialty substance use services, and self-help groups. Further, while historically the alcohol/drug and mental health research fields have generally addressed only a particular service sector, we propose to study the interactions among substance abuse services, mental health services, and primary care services, with the ultimate focus on substance abuse services. We investigate these issues through secondary analysis of three large, nationally representative surveys: the National Epidemiological Survey on Alcohol and Related Conditions (NESARC), Health Care for Communities (HCC) and the National Survey of Drug Use and Health (NSDUH). The Specific Aims are: (1) To investigate patterns and predictors of perceived need for drug and alcohol services, and the relationship between perceived need and receipt of substance use disorders (SUD) services;(2) To investigate patterns and predictors of primary care screening for drug and alcohol problems, and how screening relates to primary care substance abuse services and specialty referral;(3) To investigate patterns and predictors of mental health services utilization among individuals with substance disorders, and how this relates to receipt of substance abuse services;(4) to investigate patterns and predictors of "coerced" or "non-voluntary" SUD services among individuals with SUDs;(5) to investigate racial/ethnic and urban/rural differences in pathways into SUD services. The results of the study will inform policy to increase rates of utilization of effective substance abuse services among those with substance use disorders.