Around the turn of the millennium, anxiety flew past depression as the most prominent mental health issue in America, and it's never looked back: With more than 18 percent of adults suffering from an anxiety disorder in any given year, the United States is now the most anxious nation in the world, according to the National Institute of Mental Health. Stress-related ailments cost the nation $300 billion every year in medical bills and lost productivity, while our usage of sedative drugs keeps skyrocketing.