What are the outcomes of game addiction?

thats a good question that i wish i had an answer too. my little bro has grown up living on his computer. doing his school on it, playing his games on it meeting his friends on it & basically stays living in his room on that damn computer due to his game addiction. sometimes i wonder if its even normal for a person who isnt depressed to coop themseleves up allday/everyday on the computer gaming... with friends... or is he depressed?