I just finished answering a lot of questions about WoW. Very few of them were about research, most were about the fear of addiction, and the fear of misspent time.
Time is a big deal for those who care about a player who is not able to control his or her own time in relation to the game. Time spent ingame is time spent not interacting with those non-players you live with. This is however not a problem that is limited to people playing WoW. Academics know it well - one of the most dangerous periods for an academic marriage is when one of the spouses is doing their PhD. The work takes so much time and so much mental energy that you neglect the people who are not involved in te topic. It is also very easy to become infatuated with somebody who really understand what you are trying to do, and can help out.
While gaming isn't the same as a PhD, there are similarities between games and other challenges. What we all need to learn, often the hard way, is to prioritise our time. In group based play, such as the level 60 or endgame play in WoW, your use of time influences not just the people around you in the physical world, but also people on computers all over the world. Drop out of a raid, and 39 other people are influenced by it.
To deal with the dual demands of the partners in the flesh world and partners in the game world, players need to learn to be extremely disciplined. To make it work well they have to establish routines to maintain all spheres, and not let the use of time blur too much. Some just can't do it, raiding and work and their loved ones and their health - the fact that there are only 24 hours and some of those must be spent sleeping doesn't add up. And if it is a choice between spending your precious time helping 39 people who think you are a great main tank get through Black Wing Lair, or spend it doing dishes, laundry and other chores... Well, I know what I think is more fun. And those dishes will wait, right?
A lot of what is mistaken for addiction is this kind of prioritising between conflicting demands. I grew up with a mother who loved her garden over everything. From spring to fall, she was outdoors planting, weeding, tending, picking. She left cooking, doing dishes and cleaning to her children, including tending to each other. She hated to have to make dinner at a certain time, so she made us do it. My patient father ate endless amounts of burned fish pudding and badly cooked potatoes, while the garden was an amazing jungle of flowers, herbs, vegetables and berries. Was my mother addicted to her garden? She ignored her children, she let the work in the garden come before participating in our lives, before other chores and the health of others (all that burned fish pudding can't have been healthy), and she was mentally and socially absent. But who would use the word "addiction" about this activity? She just thought having a nice garden was important, and anyway, we learned to cook, clean and do dishes early, and became very independent.
Prioritising time isn't easy, and time is probably the real currency available to individuals today. Money is a way to buy or swap time. The other big hard currency is energy, but individuals only trade in energy when we swap time (money) for it. So when somebody spends a lot of time on an activity we don't share, we think it is wasted - wasted as it would be if the person spent all their hard earned money on fancy clothing or a big powertool that's never used, to use some examples I suspect some of the worried parents may recognize... And so time becomes a field fraught with conflict and a source of power-struggles in all kinds of relationships. When gaming adds to all the other things which use time, of course gaming will cause problems for kids, teens, adults, partners and everybody else who share time. Until we have worked ways to negotiate this into the daily set of etiquette it will continue to be an issue.
When my kids were younger, the meetings at their school were about how many hours the kids in their class should be allowed to watch television. Now parents of kids that age discuss how many hours their children should be allowed to play games. The need to help kids administrate their time is real. The activities that needs to be negotiated are interchangeable.