Suffering Artists

There is a perception out there that all truly great artists must suffer in order to acheive greatness. To quote my aunt "You must plumb the depths in order to reach the heights" (she said at the time it was a quotable quote and I've been itching to quote it ever since.) While it is possible to find various exceptions (Did Shakespeare ever suffer? Did Bach?), the rule does seem to be true, that the overwhelming majority of artists did have hard lives and/or early and tragic deaths.
I have a few main thoughts about this. 1) Are their lives more tragic, stastically speaking, than the average person. One large tragedy in someone's life may make it tragic on paper, but perhaps every given person has about the same, over a lifetime. And if you count early death after a happy life seperately, then you're upping the average.
2) A lot of the suffering is self-afflicted. Meaning to say that it may not be suffering that spawns art, it may be that the artistic temperment spawns suffering, which is not to say that it's not reciprocal. A tragic love affair, suicide, drinking problems- all of these are nobody's fault except for the author's, and these seem to comprise the majority of the artistic suffering that we find.
3) The rule, so far as it exists, seems to exist only for the truly great artists. Good art, the sort of stuff that people enjoy, even if it is not classic, seems to be created frequently by normal, functional people. Which seems to argue that the suffering imparts not the artfulness, but the message of the art- that those who suffer have more to say about life, or- more likely in my mind- those who think deeply about life and so on- often bring suffering on themselves.
Based on which, I would say that suffering is not inherent to art. Some people who think about life, one must assume, do not come to depressing or self-destructive conclusions along the way. Many of them do. And possibly that experience adds to what they have to say about life. But art is possible about suffering- even great art, so long as the artist is a student of life who has come to happy, functional conclusions.