Details on Cho's mental state and legal status
Here's the article, in the Washington Examiner.
It may be a bit more complicated than that ... remember the Gun Control Act definitions were drawn up nearly forty years ago, and the mental provisions were a minor issue. [Heck, until we cleaned it up in '86, the statute had two different definitions of felon, one for whether a felon could purchase and one for whether a felon could possess).
The federal definition of prohibited person (18 USC 922(d)(4) is "has been adjudicated as a mental defective or has been committed to any mental institution." "Mental defective" isn't used in state law, nor I suspect in psychiatry, these days. So the best you can say is that a finding that someone is a danger to self or others *probably* falls within it, just on the basis "that sound defective to me." In practice, reliance is usually put on the other clause, committed to a mental institution, since at least that gives you something firm and clear to go on.
What's a bit of a mystery to me is why a judge would find that a person was an imminent danger to self or others and then assign him to outpatient treatment. What if he doesn't go? What if he finally flips before he gets an appointment? He either is a danger or he's not, and if he is, should be committed then and there.
[UPDATE: the stories imply that he was either (a) temporarily committed for observation, or (b) voluntarily checked in for observation. I'd guess the former (why hold a judicial committment hearing if the guy is there voluntarily?) I checked with a friend who has practiced psychiatry for 30+ years, and testified at more such hearings than you can count. They told me that findings of dangerousness, but refusal to commit, is not totally unknown, but very, very, very rare. If a person is insane to the point of being a danger to life, you don't release them and say "now, do be sure to get some treatment." They need to be off the streets and treated, right now. Such a ruling can only be explained by the fact that a judge can do anything he wants without consequence.