Most anguish isn’t an illness but an evolved response to adversity

Depression and anxiety have low heritability and can onset at any age. "A genetic mutation that increased an individual’s tendency to experience bliss, and not to worry about enemies, wouldn’t have lasted for long in the gene pool," explain Kristen Syme and Edward H. Hagen in Psyche magazine, who believe this "unceasing process has many ramifications for mental health research."