You cannot ask the question, "What is the cause of mental illnes?" It is not a question, UNLESS you don't mean "mental illness" but this or that specific mental illness. Even then it won't be a really discussble question. "Mental illness" doesn't name anything that can be discussed. It is not tjat "Instead of thinking abstractly about this, everyone dives for the specific," but that everyone spontaneously replaced a mere label which named nothing to abstractions which could be discussed. There is no cause of mental illness. There may or may not be _a_ cause of OCD or BPD. I doubt that there is _a_ cause and as soon as anyone (up on the research or not) starts discussing c auseS of depression, they go over a cliff to a sargasso sea of guesses.
Everyone tried to replace a non-question with some question that could be (possibly) discussed.
Carrol