So, just out of curiosity, how would the DSM deal with a disorder that manifested as hearing God speaking directly to you, telling you to do things, without appearing to patholigize "religion"?
Would it be contingent on what, precisely, God was telling you?
Presumably, if God told you to jump off a building as "a test of faith", that would count as metal illness, but how does that differ from other forms of intense devotion?
What if God told you to give away all your belongings and live as a beggar? What if God told you to bomb abortion clinics? What if God told you to cut off all relationships with your family due to their fallen nature?
The specific content of the delusion doesn't matter so much. It's not like you ask how weird or irrational the delusion is, and then if it's weird enough you say "OK must be schizophrenia." There are plenty of other symptoms that go along with schizophrenia that make it really obvious, like the auditory hallucinations, and the fact that a schizophrenic is just unable to function in life.
But I know that sometimes there have been misdiagnoses. In one of the famous early cases of the insanity defense, McNaughton shot the Prime Minister of England's secretary, and claimed the British govt was out to get him. He was found not guilty by reason of insanity due to his paranoia. But apparently it was later determined that he was a member of a Scottish separatist movement, and he actually was in fact being followed by the English. He was probably just a political assassin with extreme beliefs and not insane at all.
There are also some bizarre examples of religion and mental illness. Just in the last couple of years, two Texas moms killed their children. The first (Yates) was found guilty of murder for drowning her children, despite a clear history of diagnosed mental illness. The second one (Laney) stoned her children, and was found not guilty by reason of insanity, despite no history of mental illness whatsoever. The difference, IMO, was that Yates said she was commanded by the Devil, and Laney said she was commanded by God. The reason that's important is that one of the elements of the insanity defense is that if you know right from wrong, you're not insane. Because the one thought she was guided by the Devil, she knew it was wrong, because the Devil is evil even in her delusional world, and the other thought she was guided by God, so she thought what she did was right.
That's truly fucked up. If you believe God made you do it, you're OK, but if you believe the Devil made you do it, you're in trouble. It reminds me of some of the questions on that God survey in the other thread.