When you write "needs improvement" I think "need a complete overhaul" would be better.
Other people in this thread have already mentioned the drugging of children but I'd like to stress something else.
You compare psychiatrists to chiropractors as far as legitimacy is concerned, but there is a very big difference.
No one can force someone to see a chiropractor and that chiropractor can't strip you of every civil right without an accusation or a trial based on his assessment.
A psychiatrist can and does that on a regular basis.
This is a huge difference.