Christ, I really dislike people like you, and that whole view. Some people have actual conditions that can't be fixed by a 'change of mind'. Chemical imbalances that, if they do not take responsibility for, fuck up their lives and people around them. Are there FAR too many people medicated than need to be, and medicated for longer than they need to be, and not getting the therapy that would benefit them better? Absolutely. But for some people it is a true necessity - I grew up with a mother who suffers schizophrenia and bipolar II, and the medication makes so much difference in allowing her to live a stable, happy life, and to allow the people around her to do the same. It takes more than a 'positive attitude' to make her stop hearing voices. It sucks, but it's true.
If people want to believe that themselves, that's fine. But everyone I hear spouting that opinion is so fucking smug, condescending and arrogant about it, like everyone else is so stupid for not sharing their view, and they couldn't possibly be wrong. That's the attitude that leads to the prejudice against the mentally ill that makes it so difficult for them in the first place, because even if they're trying their best they're viewed as 'weak' by people who are just lucky enough not to have been born with brain chemistry that goes on the fritz.