“One feels as if one were lying bound hand and foot at the bottom of a deep dark well, utterly helpless,” Van Gogh described depression in a stirring letter to his brother. “The gray drizzle of horror induced by depression takes on the quality of physical pain,” William Styron wrote a century later in his classic masterwork giving voice to the soul-malady so many of us have suffered silently. Before Styron, even before Van Gogh, the great Romantic poet John…