So the guy was angry at himself for losing, punched a wall and teared up a bit? I'm kinda embarassed to say it now but I used to do that too when I was playing Varsity tennis in high school and I lost a big game. Doesn't mean I did roids. On top of that, the guy does competitive MMA fighting which is the most aggressive sport in existence. It would tend to attract aggressive personalities don't you think?
I'm not saying steroids don't cause over-aggresiveness but the people who go into "roid-rage" are ones that are probably already fairly near the tipping point to begin with... And now they have the muscle to back it up.
Steroids can absolutely cause someone to act crazy. Especially since steroids are mostly found in the black market. Pure testosterone in theory should not cause it, but we are talking about animal testosterone that is put together. Most hardcore steroid users stack as well. For instance a body builder may combine dbol and winstrol. When you combine, there is no telling what kind of reaction your body/brain could have to the mix. Ideally that would be a good combination cause the dbol would make your muscles bigger, and the winstrol would cut body fat.
Some steroid use has turned people schizo.
Pretty much anything that gets into your blood goes through your brain at some point. The brain can have reactions to anything.
Not saying the guy wasn't on some other drug as well.
I know a few bodybuilders who have been on AAS. The assholes remain assholes and the ones who have been mellow before were still mellow. Roid rage is a myth.