It depends on the circumstances involving the threat. If I say I’m going to kill you, but I haven’t put a hand on you, there is not a doubt in my mind that person would be released on his or her own personal recognizance. If they put their hands around your neck or something that physically hurt you, there may be a bond or no bond posted until the case can be heard.
To get somebody placed in a facility that deals with mental issues, you first have to have an emergency commitment signed by the courts if they are not willing to go themselves.