Talk:Chara/@comment-81.220.217.195-20151029220428/@comment-68.40.216.96-20151103024917

Psychopaths are born that way, with a mental disorder instilled at birth. You can develop a cognitive disability, but you can't one day develop autism or Down's. It's the same concept with psychopathy.

As for why Chara wishes to hurt monsters, it's anyone's guess, but the lore backs up the notion that Chara is a natural sadist. However, the game gives a great account of why that is, backed up with Flowey's sadism due to not having a soul: you can, therefore you have to.