Why are we losing the fight against depression? In this groundbreaking work, psychologist Jonathan Rottenberg explains that despite advances in pharmaceutical science, progress has been hampered by our fundamental misunderstanding of depression as a psychological or chemical defect. Instead, Rottenberg introduces a surprising alternative: that depression is a particularly severe outgrowth of our natural capacity for emotion; it is a low mood gone haywire. Drawing on recent developments in the science of moodand his own harrowing depressive experience as a young adultRottenberg explains depression in evolutionary terms, showing how its dark pull arises from adaptations that evolved to help our ancestors ensure their survival. Weaving together experimental and epidemiological research, clinical observations, and the voices of people who have struggled with depression, The Depths offers a bold new account of why depression enduresand points the way toward new paths for treatment.