Winston Churchill called it The Black Dog. Abraham Lincoln and Sir Isaac Newton wrestled it throughout their lives. J.K Rowling, Rosie O'Donnell and Sheryl Crow suffer from it; now Robin Williams has reportedly lost his battle with it.
Depression. There; I have said it, spoken of the Voldemort of diagnoses, The Condition That Shall Not Be Named, but from which a large minority of the public suffers. According to the CDC, one in 10 people grapples with depression.