Doggiedo, I'm not sure, but I think I came pretty close to it last year.
Usually, the doctors say that it is time when you start being a danger to yourself and / or others. Well, last year, especially over the summer, I had a lot of suicidal ideation. The doctor came pretty close to hospitalising me, but the problem is that the unit is close to my workplace and I would have known some people there so I refused and just carried on with things and just about made it without a suicide attempt.

Personally, I think the criteria should be wider. You shouldn't only be allowed to be admitted when you are suicidal or about to attack others but also when you're really really not feeling well at all. But I suppose, these days with the NHS (I live in the UK) in crisis, this doesn't happen. I believe I should have tried to admit myself last year and even possibly a few weeks ago and tried a proper recovery process as an inpatient.

Are you considering hospitalisation? Can your doctor advise? I'm not sure how the system works in the US, but would you also have to be referred by him or her? What are your options?