Mexico City hosted the Fourth Annual Meeting of the International Drug Abuse Research Society (IDARS) April 15–19, 2013. More than 100 specialists from 15 countries attended the conference, which focused on neuropharmacological, neurobehavioral, and neurochemical drug abuse research findings in 12 plenary symposia and 2 poster sessions. The NIDA International Program sponsored the symposium, “Research on Inhalant Misuse: From Epidemiology to Epigenetics,” chaired by former NIDA INVEST Fellow Silvia Cruz, Ph.D., Cinvestav, and NIDA grantee John J. Woodward, Ph.D., Medical University of South Carolina (MUSC). María Elena Medina-Mora, Ph.D., general director of the Mexican Instituto Nacional de Psiquiatria Ramón de la Fuente, discussed the challenges new substances and patterns of inhalant abuse pose to neuroscience and public policy. Dr. Cruz reviewed the molecular and behavioral actions of toluene, the most widely abused inhalant. Dr. Woodward and Ph.D. candidate Jacob Beckley, MUSC, reviewed the latest evidence on the neural effects of toluene on the mesolimbic dopaminergic system. Keith Shelton, Ph.D., Virginia Commonwealth University, presented behavioral pharmacological data that allow comparisons of the abuse liability of different inhalants. Monica Lamas, Ph.D., Cinvestav, discussed epigenetic changes produced by prenatal exposure of toluene. Rafael Camacho, M.D., director of the Institute of Attention and Prevention of Addiction in Mexico City, addressed the need for additional funding for research on inhalant abuse, which is an underappreciated class of drugs. Symposium participants also received copies of Volatile Substance Misuse: A Global Perspective, the NIDA International Program-supported peer-reviewed supplement to Substance Use & Misuse (2011; 46:S1) that examines inhalant abuse through sociocultural epidemiology, neuroscience, and interventions research.