This disease causes itself, I am sure the author, a psychotherapist with thirty years of experience working with depressed patients. This is because depression raises levels of cortisol and adrenaline—the hormones of the fight-or-flight response—in our brains, which become depleted and stop producing the dopamine we need to be able to enjoy ourselves. Therefore, depression is so delayed, sometimes for life. However, the brain can be trained. To do this, you have to uncover the emotional underpinnings of depression — fear, shame or guilt — and start learning new feelings and behaviors.
Mann, Ivanov & Ferber, 288 pp., 2015.