[joshuacc]

That's not surprising, since (despite the name) ADD doesn't imply an inability to focus at all times. Those with legitimate ADD have an unusually hard time directing maintaining focus except under highly stimulating conditions. Complicated computer games are one of the few things that an ADD person is likely to maintain focus with.

That's not to say that your roommates cases were legitimate. They may not have been. But your description isn't necessarily evidence of a mis-diagnosis.