Could mental illnesses serve an evolutionary purpose?

Arizona State University psychiatry professor Randy Nesse has a new book that looks at mental illness through the lens of Darwinian evolution. This book is the result of case studies from his psychiatric practice that provided insights into why modern medicine has struggled to diagnose and treat mental illness, and it looks into the deeper evolutionary question of why our minds are so vulnerable to mental illness. Nesse discusses his book, “Good Reasons for Bad Feelings.”