The terrible truth about depression, and the part of its nature that terrifies me the most, is that it appears to operate beyond reason; feelings happen to you for no apparent cause. Or rather, there is usually an initial cause, a 'trigger'as they say in therapeutic circles, but in severe depression the feelings of sadness, grief, loneliness and despair continue long after the situation has resolved itself. It is as if depression has a life of its own, which is perhaps why so many sufferers refer to it as a living thing, as some sort of demon or beast.
Sally Brampton, Shoot the Damn Dog: A Memoir of Depression
depression