'Seeing the insane' - Sander L. Gilman

Portrait of a patient in St. Paul's hospital

Following my interest in the psychological side of Dorian Gray's deterioration, I wanted to research a bit about insanity, including visual interpretations of it.

I found the front cover art particularly striking - it reminds me of work by Francis Bacon. I also liked the following images:

It interests me how a lot of these photos or drawings incorporate features that one would see in a physically, not mentally, ill person; or even just an old person for that matter - the wrinkles and lines, the sagging eyes, the drooping features and missing teeth. And yet, these images, and these qualities within them, supposedly connote insanity. 

I would like to incorporate these qualities into my own work, to be able to reflect both Dorian Gray's physical and mental decline.