First I must say that I am 43 and never had a "mental health exam" until I was forced to by my evil stepmonster. Secondly the police have a hands off policy it seems - we had a neighbor saying death threats to me and the cops said, tough, nothing we can do unless you catch him actually hurting me or our property. That was so not helpful.
My family is very familiar with mental health issues as our mother was schizophrenic. Getting her help was not always easy, but she was obviously off her rocker so not impossible. Paying for that help put our family in bankruptcy. With that history it still was next to impossible for one of my brothers to get meds even though HE knew he needed them. Right now I have no health insurance, my "happy pills" (depression is another form of mental illness, it is chemically caused) cost me $150 a month. Luckily I get on my husband's insurance in a few weeks, but if I had more serious issues then depression I would not seek help right now cause of the costs. I can't put my whole family in major debt and even a mentally ill person can be slightly logical. And no, the health care bill will not help that cause self employed or unemployed people are still going to be under the radar or off it altogether.
It's a hard issue, even if treated the person can relapse with no warning. When my mom was on her meds after a while she would be fine and stop taking them. She would feel like she didn't need them anymore. She would either flush them, lie about taking them or take them and then spit them out later by cheeking it. There is no way to stop that and unfortunately at that point they ARE ok, so nothing you could even do, until you realize it was too late.
It's hard to fix problems in the brain, it's not like a broken bone you can see.