First off, I am not endorsing the validity of either of these authors' views, nor am I equating religious experiences with schizophrenia. That out of the way, I think these are both very interesting pieces.
The Religious Experience of Philip K. Dick tells of an experience Dick, an American writer, had in 1974. He spent the rest of his life trying to explain it. It has been adapted by R. Crumb. In My Mom Was A Schizophrenic Chester Brown questions the validity of much of what modern society says about this mental illness.
I thought I'd post these links, because our society really isn't comfortable with too much religion. When Jews said to Jesus "Aren't we right in saying that you are a Samaritan and demon-possessed?" (John 8:48), we can look back and wonder how they could be so blind, but when the guy next to us pushes the spiritual envelope we're all to quick to say he's being legalistic or maybe just nuts.
I also think they are good examples of using the graphic medium to discuss important issues.