Unpredictability of Suicides
I lost a dear friend to suicide one Christmas Eve. She was cheerful and ebullient in her last weeks. Those around her had no idea.
I know others who lost dear ones to suicide. It's a devastating surprise to the families.
Far worse are the murder-suicides where children are among the victims. First responders are at risk of suicide (sometimes years later) after coming across such scenes. Any such tragedy you come across is one too many.
A number of these people were under psychiatric care. It's a hazard of the profession that some patients suicide, but the shrinks are usually caught by surprise.
Bottom line -- if the shrinks are incapable of predicting suicide, so are the aviation authorities.