How do you know?

I just finished a book of true crime about a woman in Kansas City who poisoned her husband, not killing him, and later, burned her house down with her children in it. One of the three escaped.

I hardly ever read true crime. People who know I read mysteries find this strange, but the true crimes is just too creepy because at no point can you say, "Oh, it's just a story." I was intrigued enough to read this one because it is set here.

This woman could be vivacious and witty and the life of the party, but in her personal relationships she had no coping skills and would throw intense temper tantrums when things did not go her way. Toward the end of the story several people in her life felt that somehow the system had failed that no one had called in outside intervention before death happened. (The husband had tried to have her committed to work on emotional issues but she had been released after three days, partly because she was very good at seeming congenial when necessary.

So I'm not here to rehash simply an old crime, but the question this left me with is how do you know when someone is too unstable or too far gone and something has to be done.  Off the top of my head, I can think of three unstable people in my life who can seem "the life of the party" and can be fun in social situations. These same people in other moments would terrify me if they were at my front door unexpectedly. I would probably not open it, depending on the circumstances.

So the people in this crime story didn't seem to know it was time to intervene. Everyone kept saying, "I didn't think she would hurt her children. They were so important to her." So when do you know that someone has crossed over? Do we recognize a precipitating event when we see one or only after the cataclysm has happened do we see it?

I suppose if the answer to this was clear the field of psychology and analysis would be much more straight forward. For law enforcement, the answer is easier to say but harder to live with. You can't arrest someone because they might commit a crime or are suspicious. They have to violate the law before their rights can be taken. You can't call the cops if someone in your life has been erratic or suspicious -- until they won't leave your house or something. So how do you know when to get help or intervention for someone? Don't we always think, "No, they wouldn't REALLY do anything,"?