I was skeptical about this issue until I came across these pages:
http://www.dailymail.co.uk/sciencetech/article-2067607/Violent-games-DO-alter-brain--effect-visible-MRI-scans-just-week.html
http://healthland.time.com/2011/12/02/how-playing-violent-video-games-may-change-the-brain.html
It seems stop playing represents a health improvement for those already ill.