I not only have thought about killing myself but others too.
I never did it but I fantasise to hurt the people who treated me that way. I feel like lives meaningless so killing the ones that hurt me would only give me live in prison.
I already am in prison.
My body is my Prison
It depends on how you define it. If you tortured someone in every way possible with the least homicidal person and gave them a bunch of drugs to reduce inhibitions. Could they? Yep! So yes.
Most people fear prison if they are given drugs so they aren't thinking of the repercussions say anti-psychotics if they aren't psychotic could they? Yes.
The answer is yes but if you take the most unlikely person possible it would take a lot. The better question is what would need to be done to them. Some very little. Some a lot. The why also matters. Most people if their life improves a little would easily rape, murder, and torture someone and they'd do it in a heart beat. The holocaust proved how little it takes (not the first Genocide either). This has been replicated over and over and over again since the turn of the 20th century. From Cuba, to the Nazis, to Russia, to China, to Turkey (Armenia), to southeast Asia (Khmer Rouge), to Rwanda, to North Korea. Humans are unbelievably awful.
Hell the Millgram experiment showed people will torture people forever basically and feel no remorse if they are brainwashed into thinking it's for their own benefit.