It should be noted that a psychotic break can happen with any psychedelic given the wrong circumstances and individual, and although rare, is a serious problem for all involved. Since you are not in control of your mind, it is possible and probable to commit acts that you would normally not even consider. If one wants to know what a psychotic break is like, I can relate my experience.
A psychotic break is not something most people remember. You will probably be astounded if and when you come to and you're told what you were doing. In my case, I took a quarter-ounce of psilocybe mushrooms and in about a half hour I had a screaming-like-a-banshee psychosis in which I repeatedly threatened to murder the person I was tripping with for hours on end, just like in the movies. I had to be physically restrained, and after a while, I simply lapsed into a thought loop in which I believed I was unable to escape a circular thought pattern and that I would be stuck in that hell for all eternity. I screamed for hours on end; the experienced trip sitter, someone who has tripped hundreds of times in his life, could do nothing to console me. My vocal output, when not primal screams, was a random stream of half-sentences which contained heavy use of the words "fuck" and "kill". What little I consciously remember doing in that state had nothing to do with what I was actually doing. I pissed myself at one point, likely in terror. Perhaps most psychotic breaks don't involve homicidal ideation, but I can assure you that it happens and that mine did.
If you are going to be tripping, don't assume that a psychotic break can't happen to you or whoever you're tripping with. It can, especially if you have underlying emotional issues, and is an urgent problem if it occurs. Keep in mind: if precautions are not taken to deal with someone having one, the worst case scenario is a very bad scenario indeed. At the very least, keep anything that someone could easily hurt someone with away from those tripping.