As a licensed clinical psychologist (VA lic. #0810001993) I have a somewhat unique perspective. As a historian (untrained) I add to this. My perspective is this:
Two generations ago we emptied the mental hospitals nationwide with medications. One generation ago we greatly improved the efficacy of those medications. All good, right? Over 90% of the diagnoses that placed one in those mental hospitals are genetic in origin. The medications put these people back into society, families, and as fully functioning people.
We now are on the third generation of people who have not seen the devastation the symptoms cause, have no idea of their genetic heritage, and the onset of these symptoms is often subtle and unremarkable to the person. Major Depression with it's possible suicidal and homicidal ideation, Schizophrenia with it's cognitive decline and confusion, and Bipolar in it's manic and mixed episodes all present danger, especially when paranoia is involved.
The onset of these symptoms is often not obvious. We have the example of a medical student who dropped out in his sophomore year and shot up a theater. Just from the news reports it was evident to me that he was in the throes of a psychotic break - but he had been under daily or weekly observation by MD's in his school and they did not catch it. If you would like to experience hallucinations get the movie A Beautiful Mind with Russel Crowe. You will see how 'normal' the experience is internally. I have a client who told me her mother once fired a gun in the house. The person she shot at wasn't there, but she did not know that.
The solution? I'm not sure other than a massive educational program focused on knowing one's genetic heritage and the appropriate treatment.