My step-son finally got non violent when OFF all the meds others had him on when younger. (he wasn't in our care then, I got him as an adult, later on).
But, he has gone off a couple of times with his temper. I made it very clear that cuckoo or not, he better not pose a threat to anyone in the house again, or he can get the hell out...and hasn't happened since.
Of course, I also keep my guns under lock and key, two levels worth actually. My room door is locked (and not some cheap interior door one), and my closet is locked. Then, some even have trigger locks, or are in the safe. (so really three different levels). Granted, I keep one near me while sleeping, but bedroom door is still locked then, and trigger is locked (key isn't in an obvious spot, but I can do it in the dark, and in seconds).