…..This report presents prevalence estimates of any mental illness and serious mental illness based on each survey and ends with a brief discussion of how these prevalence estimates might inform policy discussions. ….. The prevalence estimates discussed in this report may raise questions for Congress. Should federal mental health policy focus on adults or adolescents with any mental illness (including some whose mental illnesses may be mild and even transient) or on those with serious mental illness? Should substance use disorders be addressed through the same policies as other mental illnesses? Members of Congress may approach mental health policy differently depending in part on how they answer such questions…..