Chuck Raison, a psychiatrist and a professor of psychiatry at the University of Wisconsin-Madison School of Medicine and Public Health, and Vlad Maletic, a clinical professor of neuropsychiatry and behavior science at the University of South Carolina School of Medicine, wrote a book together called, "The New Mind-Body Science of Depression," in which they offer research on the mind-body connection, such as looking at the immune system, as a way to tackle depression. But their conversation also delves into the Tibetan Buddhist tradition of tummo, psychedelics and "dark" retreats.