Delusions

A dear friend of mine suggested that I write about mental disorder on my blog, considering that it's the main theme of my books.  What a novel idea (pun intended!).
I have been fascinated by mental disorder/the human psyche for as long as I can remember.  I took psychology 101 three times just because I really liked it (once in high school, twice in college).  I find it intriguing that each person's psyche is all their own, despite the similarity in terms of anatomy.  I could go in depth into nature versus nurture, but I'm not a scientist, I'm a novelist.
I like the idea that while we rely entirely on our perception of the world around us, that perception can be altered by a number of things (drugs, illness or exhaustion, to name a few).  The most interesting part of altered perception is when it has been changed, one might not even be aware of it.  This fact creates an impenetrable foundation on which sanity is based, though it could be a complete sham, and really, one would have no way of knowing.
Most people consider themselves sane, for obvious reasons, but truthfully, many are completely delusional.  I'm not referring to the scary mental patient who believes he's the reincarnation of Hitler (though he'd make for a supremely fascinating character, if you ask me!), I'm speaking more toward the man who thinks his "recreational" daily drinking habit isn't going to cost him at least his health, if not his life, or the teen girl who believes she's fat even though she's twenty pounds underweight.
People that live under these lies they tell themselves are delusional, but don't consider themselves to be so in the clinical sense.  Maybe their mental disorder will affect their lives for years, but without a dramatic enough effect for them to change.  Maybe their conditions will eventually force them to seek treatment before costs them their lives, or maybe not.
Based on that concept, does that mean that everyone is a little crazy? Probably, but the big difference is that not all delusions cause detriment, or interfere with daily living.  Some delusions are utterly harmless while others can devastate emotional well-being.
I see the mystery of the human mind as being a debatable topic.  The medical field often questions the validity of studies of the human mind, despite the many years since Freud and Jung.  What appeals to me most about the mind is the opportunity to draw my own conclusions about how it all works, because ultimately, it's all subjective.  You believe your delusions, and I'll go on believing mine.