Calling Japanese Police When You Are a Danger To Yourself?

The last few months have been exceptionally rough for me, and tonight things are really coming to a head. Although in this moment I think I'm okay, the rest of the night and the rest of the week are more up in the air.

I heard that when you're afraid you're going to hurt yourself, you can call the Japanese police department and they'll come get you/you can go to them and they will keep you from hurting yourself. But I don't know what to expect or what to do or if that's even true.

Does anyone know what happens if you call the police when you think you're a danger to yourself?

Edit: I live in Kawasaki, pretty much just outside of Tokyo