I think this is where you'll get a lot push back because I have absolutely zero trust in my or any government to make this determination and not abuse it. I'm "mentally ill" a few times over, Johns Hopkins says 24% of adults have a mental disorder.
As much as I agree with you in theory that getting people help is good it requires a government of angels. It's the same thing with the war on drugs, the reality is much much worse than the theory.