Despite current treatment guidelines, fewer than 10 percent of adults with co-occurring mental health and substance use disorders receive treatment for both disorders, and more than 50 percent do not receive treatment for either disorder. The findings highlight a large gap between the prevalence of co-occurring disorders and treatment rates among U.S. adults and the need to identify effective approaches to increasing treatment for those with these conditions. An analysis of data from U.S. adults with both a mental health disorder and a substance use disorder indicates that only 9.1 percent of those adults received both types of care over the past year, and 52.5 percent received neither mental health care nor substance use treatment. The study, based on data collected from the 2008-2014 National Survey on Drug Use and Health, reports that 3.3 percent of the adult U.S. population, or some 7.7 million individuals, suffers from both a mental health...