These conclusions came from the National Mental Health Association’s (NMHA) second America’s Mental Health Survey, which was conducted by Roper Starch, Worldwide Inc. The firm called more than 3,000 randomly selected adults in the U.S. in April. Surveyors gave respondents a symptom checklist derived from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Revised, to determine whether they were likely to meet criteria for major depressive disorder or generalized anxiety disorder (GAD).