Hormones are a class of signaling molecules that exist in all multi-cell organisms and, in humans, include commonly-known examples like melatonin, testosterone, and cortisol. They influence the health and functioning of the body and brain in a wide variety of ways; on a psychological level, they affect mood, how we behave, who we’re attracted to (or not), and more.| Psychology Today
"The grey drizzle of horror," author William Styron memorably called depression. The mood disorder may descend seemingly out of the blue, or it may come on the heels of a defeat or personal loss, producing persistent feelings of sadness, worthlessness, hopelessness, helplessness, pessimism, or guilt.| Psychology Today