try looking at the mind website - there is a lot of information there
https://www.mind.org.uk/news-campaigns/
my niece committed suicide last year - she was bi-polar and had been suffering terribly. part of that was due to her medication, when she took them and all was well, she thought she was better and could stop taking them and then she would crash and suicide attempts would follow, she woould then with the help of her docter and social service support works get back on an even keel and repeat. She was in supported housing and seemed to be doing well then she just crashed, was drinking heavily and had repeated suicide attempts - each time the hospitals (after psych eval) just let her go, according to my brother she asked to be kept in the last time. and it was the last time...
I do think she was massively failed by the system, i appreciate that her history was the same pattern over and over again and she was very convincing when she wanted to be but at the end, she was getting worse that should have been picked up.
Having said all that, she is out of pain now, her QOL wasn't brilliant and I believe if she had been committed it would have stopped her from killing herself that time but she would have gone on to do it at a later date. She was too unhappy and didn't want to fight.