For some reason the myth has been persisting for years that playing violent games would make the person more violent (probably because it 'sounded right' like the myth that eating fat would make a person fat). If anything I think that such games are a healthy outlet for vented up frustration or violent feelings (but I've got no study to back that up, so it may be a myth too).
For years, science has been trying to find a link between violent games and violent people and has thus far been pretty much unsuccessful. The overall trend is that violent people tend to like violent video games, but nobody has been able to prove that violent games make for violent people (even though certain politicians love to say they do in order to deflect blame from even more pressing societal issues).
The latest study once again confirms the overall trend but also finds some interesting tidbits by watching the gaming habits of adolescents as they grow into full-grown gamer adults.
See 10-Year Study Shows That Even Violent Gamers Go Through A Stardew Valley Phase
A new 10-year study found violent video games didn’t necessarily make for more violent people and that even hardcore gamers can have a chill phase.