Outsider art

There's an interesting article[1] in the Fortean Times about 'Outsider Art', which is as I understand it art created by those who are outside the formal artistic system - "art by psychiatric patients, alcoholics, visionaries, sociopaths, loners, naifs, vagrants, street kids and hobos."

I'm wondering, though, how one qualifies as an Outsider for these purposes, as distinct from an ordinary artist who just happens to be disturbed, maladjusted, insufficiently socialized, or just strange.

Caravaggio[2], for instance - a "truculent, drunken murderer". Some of his work[3] is certainly disturbing enough.

Or visionaries, perhaps? I bid William Blake[4], and if you can see Blake and raise me, you're welcome to the pot.

Psychiatric patients - well, plenty of artists have been hospitalised at some point in their lives, though I can't pull out an example offhand. I'm reminded, however of this[5], a collection of murals found in an abandoned mental hospital.

I have the urge to try making some outsider art myself. I wonder if there's anyone currently working who self-identifies as an outsider artist?

[1] http://www.forteantimes.com/articles/189_outsider.shtml
[2] http://www.guardian.co.uk/arts/news/story/0,11711,1411485,00.html?gusrc=rss
[3] http://www.english.upenn.edu/~schreyer/Caravaggio_Judith.html
[4] http://www.ibiblio.org/wm/paint/auth/blake/
[5] http://www.darkpassage.com/hopscotch/dioramas/swimming.htm