New research reveals that depression is now the most common serious medical or mental health disorder in the United States. According to the World Health Organization, depression is the leading cause of disability worldwide. Sixteen percent of Americans will have an episode of major depression at some time in their lives, and six percent of all Americans—14 million—have suffered from major depression in the past year. Furthermore, rates of disabling depression have markedly increased over the past several decades, particularly among young people. According to data from the Department of Health and Human Services, more than three million adolescents reported at least one major depressive episode in the past year, and more than two million reported severe depression that impeded their daily functioning. A recent national study found that the share of twelve-to twenty-year-olds who had suffered major depression in the last year increased by 37 percent from 2005 to 2014.

After reviewing these statistics, psychiatrist and Professor Aaron Kheriaty adds this sobering conclusion: "We are witnessing a rising plague of melancholy."