This is a briliant question. I know of a research focused on the positive aspect. Participants, who got to play a game in which they were a superhero and helped people, were immediately afterwards much less hesitant to help (in a staged small accident that happened during the final talk with the examiner). So it seems you could get into habit of helping. I suppose it could work the other way aroud as well and you could build a habit of being selfish and not caring by playing such people. But I suppose most actors don't play only vilains all the time and have good habits outside the role. Also, playing a vilain can certainly help you connect to and understand your darker sides, which is a great way of getting control of them.