Disorderly conduct is an arrestable offense. Psychotic behavior (which is typically disorderly) is usually why psychotic folks are arrested, then (if they show signs of psychotic behavior) transferred to a facility for evaluation. Were it not for such facilities, they'd be charged with conventional disorderly conduct and housed in a jail cell awaiting arraignment with legal representation (should they request it). Assuming they meet certain criteria, instead of awaiting arraignment in a jail cell, they're doing so in a facility qualified to evaluate psychosis. They can request an attorney any time they like. Their legal status while being evaluated is that of being under arrest and being held for arraignment, pending evaluation.
Same as being arrested for public drunkenness, except they add the factor of being evaluated for mental illness. You don't send an attorney in to talk to a falling down drunk person, and you don't do that for someone who's floridly psychotic, for reasons that shouldn't require explanation. Same same.
As to the legal process, they are treated alike, i.e., when apparently capable (lucid), they are brought before a judge with their legal representative (should they request it), to determine their future situation, confinement or release. They may demand a jury trial at that point, regardless, if they protest their further confinement. Some states don't offer a jury trial for commitment, and this, in my view, is a violation of due process, and ought to change.
