From the National Institute of Mental Health: they identify these major effects of seeing violence on television:
Research by psychologists L. Rowell Huesmann, Leonard Eron and others found that children who watched many hours of violence on television when they were in elementary school tended to also show a higher level of aggressive behavior when they became teenagers. By observing these youngsters into adulthood, Drs. Huesmann and Eron found that the ones who'd watched a lot of TV violence when they were eight years old were more likely to be arrested and prosecuted for criminal acts as adults. Interestingly, being aggressive as a child did not predict watching more violent TV as a teenager, suggesting that TV watching may more often be a cause rather than a consequence of aggressive behavior.
Violent video games are a more recent phenomenon; therefore there is less research on their effects. However, research by psychologist Craig A. Anderson and others shows that playing violent video games can increase a person's aggressive thoughts, feelings and behavior both in laboratory settings and in actual life. In fact, a study by Dr. Anderson in 2000 suggests that violent video games may be more harmful than violent television and movies because they are interactive, very engrossing and require the player to identify with the aggressor.
Dr. Anderson and other researches are also looking into how violent music lyrics affect children and adults. In a 2003 study involving college students, Anderson found that songs with violent lyrics increased aggression related thoughts and emotions and this effect was directly related to the violent content of the lyrics. "One major conclusion from this and other research on violent entertainment media is that content matters," says Anderson. "This message is important for all consumers, but especially for parents of children and adolescents."
Reversing these problems require prayer for God the Father to rewire these bad networks in the brain to conform to the Fruit of the Holy Spirit. Also, pray that anyone who comes in social or physical contact with this person be drawn toward salvation at that moment and any unclean spirits on them be bound to silence and impotence at that same moment. This changes their society they are following.
edited: April 15, 2016 orderofsaintpatrick.org/relations/trauma-violence.htm