Where is the line between genius and madness? How does madness influence art? How has the relationship betweenart and madness changed throughout the centuries? These are the questions visitors are asked to consider at an exhibitin Siena's Santa Maria della Scala Museum: Genio e Follia: Il giorno e la notte dell'artista (‘Art, genius and folly: The Day and Night of the Artist').
Running until May 25,2009, the exhibit wascurated by one of Italy's most authoritative art critics, Vittorio Sgarbi, and gathers some 400 works probing the link between artistic production and mental state. The exhibit considers the often ambiguous anddifficult experience of ‘living in the real world' for those who are mentally ill.
Ranging from sculptures, paintings and drawings to video and art installations, the vastselection of works was meticulously chosen to illustrate the link between art and madness throughout the history of art.
The expressive force of the works showcased is indeed poignant, and at times, distressing. The viewer must be prepared to delve into the psyches of some of the world's most talented, yet unstable artists. It is a unique experience that will inform one'sview of the experience of mental illness, not only in artbut also in life.
Among the artists whose works are included are Vincent Van Gogh, Ernst Ludwig Kirchner, Edvard Munch, Max Ernst, Otto Dix, George Grosz, RenatoGuttuso, Mario Mafai and Antonio Ligabue.The works are on loan from some of Europe's most famous museums, including Musee d'Orsay, Musée National d'Art Moderne, Centre Georges Pompidou, the Prado, Kirchner Museum, the National Gallery for Modern Art in Rome, as well as the Brera and the Braidense National Library in Milan.
In nine sections, the exhibit opens with an exploration of the many ways in which the mentally ill were treated from the middle ages to today,including medical instruments, descriptions of daily life in psychiatric hospitals, the advent of the positivist culture in the eighteenth century, and the psychologicaltheories advanced byfamed scholar Cesare Lambroso.
http://www.theflorentine.net/articles/article-view.asp?issuetocId=4311

If I read this yesterday, would have a ton of references for you, but alas I brainfart! There was a big show regarding the Van Gogh exhibit here in Philly, with psychiatrists, psychologists, etc. discussing this topic and I can't remember a single name or book title. But apparently there is a whole University Centre studying this topic. Dan Gottlieb hosted the show on the local NPR station- WHYY, google those. Also, Psych Today a few months back had an article on it. They suggest that creative people appear to have many symptoms of Schizophrenia, but are not Schizophrenic; ie- negative symptoms but no positive symptoms. I think I have it somewhere, because I kept showing it to my friends and yelling: I don't have the same values as you, my mind thinks of different things, stop asking me to act like you! Hope that helps.

'it is only too true that a lot of artists are mentally ill;
it's a life which,
to put it mildly,
makes one an outsider.
i'm all right when i completely immerse myself in work,
but i'll always remain half crazy.'
-van gogh.
it's necessary to be crazy.

I don't think it's a line at all -- I think it's more like a huge gray area.

The line between genius and madness??? It's about two feet behind me.

einstein said the difference between stupidity and genius is that genius has its limits

Madness=If it gets to the point where you're cutting your own ear off. I think ANYTHING can influence. Even speeches are a form of art.