“because wherever I sat—on the deck of a ship or at a street café in Paris or Bangkok—I would be sitting under the same glass bell jar, stewing in my own sour air.” ― Sylvia Plath, The Bell Jar

“There is no point treating a depressed person as though she were just feeling sad, saying, ‘There now, hang on, you’ll get over it.’ Sadness is more or less like a head cold- with patience, it passes. Depression is like cancer.” ― Barbara Kingsolver, The Bean Trees

Kay Redfield Jamison on Depression

Others imply that they know what it is like to be depressed because they have gone through a divorce, lost a job, or broken up with someone. But these experiences carry with them feelings. Depression, instead, is flat, hollow, and unendurable. It is also tiresome. People cannot abide being around you when you are depressed. They might think that they ought to, and they might even try, but you know and they know that you are tedious beyond belief: you are irritable and paranoid and humorless and lifeless and critical and demanding and no reassurance is ever enough. You’re frightened, and you’re frightening, and you’re “not at all like yourself but will be soon,” but you know you won’t.
Kay Redfield Jamison, An Unquiet Mind: A Memoir of Moods and Madness

Kay, who is a psychiatrist, wrote about her experience with bipolar disorder. It’s a fascinating account of someone in the profession who also had to come to terms with the stigma of mental illness. She was quite wary of disclosing to colleagues, and when she did it was often with mixed results.