We tend to see depression as an illness to eliminate, evidence that something has gone wrong in the brain. But what if low mood serves a purpose? Psychologist Jonathan Rottenberg examines the evolutionary roots of depression and reflects on his own painful experience with suicidal despair. He explores how depression can narrow our focus, and sometimes open the door to change. A note that this story includes a discussion of suicide. If you or someone you love is struggling with thoughts of suicide, there are people who can help. If you're inside the U.S., call or text 988, or visit the 988 Helpline online. If you’re outside the U.S., you can search for resources in your country on this site. Episode illustration by Runend Art for Unsplash Hosted by Simplecast, an AdsWizz company.