Why has my Mate's Behavior Changed? Perspectives?

I know that addictions to substances can lead to personality change, but can addictions to non-physical things (ie. videogames, relationships) also contribute to major personality change? My boyfriend is obsessed with videogames more than he's ever been. And lately his usually laid back, friendly personality has become cold, defensive, and even abusive. He is short-tempered and easily upset. Any time I mention anything I dislike about a game, he goes through the roof instead of talking calmly. This didn't happen before. He's vacant, has no other interests, is failing out of college, and not spending quality time with family/friends unless it's for something he wants or needs. I went through a period where I was very infatuated with someone else (a year ago) and had similar symptoms--I was irritable, preoccupied and overreactive. Are these common signs of psychological addiction? Some people say that it doesn't exist but it seems to me that it does. Please share your stories.