DESCRIPTION (provided by investigator): Inhalant use is among the most pernicious and poorly studied forms of drug abuse. Little is known about the natural history, long-term health and social consequences, functional impairments, psychiatric comorbidities, and treatment experiences of inhalant users in the general population. The proposed study will draw upon data recently collected in association with the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), a 3-wave longitudinal investigation of a nationally representative sample (N= 43,093) of adults living in the U.S. NESARC is one of the largest psychiatric comorbidity studies ever conducted and the first to assess DSM-IV Axis II Personality Disorders, yet no inhalant studies using NESARC data have been published. Wave 1 data are available for use, response rates were high, and the dataset includes 106 variables specific to inhalant use and DSM-IV Inhalant Use Disorders. The proposed research will constitute the most comprehensive set of population-based investigations of inhalant use heretofore undertaken and will greatly increase the knowledge base upon which new inhalant prevention and clinical interventions can be developed by: 1) identifying risk factors for inhalant use and Inhalant Use Disorders and developing an empirically-based taxonomy identifying subtypes of inhalant users, 2) describing the natural history of Inhalant Use Disorders in the general population, including factors predicting onset, escalation, persistence, and stable remission of inhalant use and Inhalant Use Disorders, 3) estimating the prevalence of psychiatric disorders in individuals with lifetime inhalant use/Inhalant Use Disorders and the prevalence of inhalant use/Inhalant Use Disorders among individuals with different psychiatric disorders, and conducting case- control studies evaluating the extent to which inhalant users are'at elevated risk for psychiatric disorders compared to other drug abusers and respondents without drug use disorders, 4) evaluating the independent contribution of inhalant use and Inhalant Use Disorders to the development of serious medical conditions, adverse social consequences, and health and mental health-related functional impairments, and 5) describing the substance-related and general medical health care treatment experiences of inhalant users including types of treatment sought, utilization rates, perceived barriers to treatment, and differences between inhalant users and other drug users with regard to these factors.