The reason 'healers' are wrong about mental illness is because their hyphotheses are either untested, or proven to be wrong. Not because lots of researchers agree with the opposite.
The 'ordinariness' of a person is immaterial - Einstein was a patent clerk who had a book published refuting his views by 100 experts. He was still right.
The point I am making here is that you should never argue a point by consensus, or by authority, for that matter. You should argue a point based on the results of testing a hypothesis and finding it true or false.
Scientists of any discipline do not become automatically right because they don a white cloak and publish in a journal - not when one does it, not when an entire industry does it. It is a fundamental mistake to believe in an argument from authority or an argument from consensus. Quite frequently, authorities do get it right (precisely because they have studied it for a long time), and most of the time, they all agree with each other (forming a consensus). But these things flow from the fact that something is right (and observable, and reproduceable) - not the other way around.
I say this to try and elevate the level of debate quite apart from climate science, or GMO, or any of the other fashionable arguments.