For the purposes of this discussion, I thought it was safe to assume we were talking about doses that could actually alter your behaviour; high doses of opioids do not make exactly for agresssive behaviour, while lower doses are unlikely to have an impact either way.
A quick Google shows that only in the past few days, the cops are now trying to say he does from a fentanyl overdose, rather than the knee on his neck. TBH, this seems purely like an attempt at scapegoating, making him out to be the "stereotypical black man, crazed on drugs".
But we're veering off topic now. I'd rather not discuss the rights and wrongs of the police in this case, because I will disagree hard with any attempts to justify the actions of the police, so there is no interesting discourse to be had there, and HN is not the right platform regardless.
Adding a bento, like valium, to that mix is extremely dangerous because of the synergistic effect on respiratory depression.