If we're going to go there, personally I prefer the possession-by-demons theory. It is equally plausible and substantiated.
Edit:
I don't deny the possibility that prenatal trauma could screw you up in any given way. Attributing all mental illness to it is ludicrous. It is the same situation as with vitamin deficiency - the arrow of causation points in only one direction. There are many ways to break something complicated.
Edit: I don't deny the possibility that prenatal trauma could screw you up in any given way. Attributing all mental illness to it is ludicrous. It is the same situation as with vitamin deficiency - the arrow of causation points in only one direction. There are many ways to break something complicated.