There’s an article today on J.K. Rowling that says she struggled a lot with major depression, and even thoughts of suicide, before she became successful with her “Harry Potter” books. Thankfully, she got some good help (though it was apparently a near miss, in the sense that a substitute medical person more or less blew her off in the absence of her regular doctor — why do medical establishments continue to assume that you can just “substitute” someone else for the person with whom you have a regular relationship? It usually doesn’t help so much.)
Of interest was how Rowling later based some of her eeriest, scariest creatures, the “Dementors,” on this experience of depression. As noted in the Wikipedia reference to the Dementors, they are soulless creatures, soul sucking fiends who can afflict both humans and wizards with the loss of the ability to imagine that you can ever be cheerful again. She describes it as “The absence of hope. That very deadened feeling, whicih is so very different from feeling sad.” They feed on positive emotions, happiness and good memories.