Yep they have a tendency to cling like hell to the very things that are making them depressed and suicidal in the first place
This is very, very true. Depression narrows the scope of your thinking, leading to odd circular reasoning and despair over problems that are either solvable or not actually problems in the first place. In your mind, not solving this particular problem in this particular way means that you are a complete failure.
"There is nothing new under the sun, but there are lots of old things we don't know yet." -Ambrose Bierce