This is a top article released in 2016.
It shows a decreased functional connectivity between the amygdala and other brain regions in AAS users versus non-users, which result in aggression, violence, and impulsivity.
Using steroids affect your emotional and cognitive regulation. And the more and the longer people use them, it goes deeper.
Testing 151 athletes, by fMRI(Basically a CT scanner for brain usage)
151 is not a big number for a sample scale. But it's the biggest test scale till now.