Those inclined to broadcasting their periodic mental breakdowns to the world are generally well known to their local law enforcement, unless they live in a very large urban area. A call from a concerned adult with the right information and tone can trigger a visit to both the subject, as well as a friend or family member.
This rarely results in any sort of intervention, but the officer taking the call will quickly dispel any confusion the subject might have been spreading, and it puts friends & family, who may have not yet noticed, that there is trouble afoot.
I have successfully committed one person, but it was long ago, they were obviously both drugged and a danger to themselves. I have seen several situations in the twenty years after that where a friend was trying to deal with an adult relative who really should have been in a safe place. It is very, very difficult to corral someone unless they are completely disconnected from reality.
I think that I may still hear a great deal of noise from this location, but I do not believe that anything else will happen, no matter what sort of dramatic pronouncements are crammed into 140 characters.