One thing I know is that the person that is sick has to want to help themself, but the kicker is they may just be too tired to try to fight it any more. They may have all the resources money can buy, but the constant weight and battle to be better is something that no one understands, even the person fighting the battle.
Early intervention may help with some cases, but not always. Drugs may help, but making sure the person takes them as prescribed is a chore itself. Hospitalization, when available, may help. I don't think mental illness is ever cured, not even completely controlled. It's too vicious an animal to ever be tamed.
It's scary for those of us on the outside looking in, but terrorizing for those inside that are more often than not begging to "be normal".
I don't know what the answers are, but it scares the hell out of me for families and individuals dealing with it.