The selfishness involved in addiction has nothing to do with narcissism. The "need" for whatever one is addicted to overwhelms everything else. Most narcissists are very intelligent, and like a sociopath, are masters in the art of manipulation. As employees, they are not typically the one's that can't get along with others. They are the "suck ups" that will do anything for attention or an "attaboy" and will do, or say anything to avoid criticism. Boss's tend to love them. It's when they become the "boss" that they become a problem.
I've been the boss of many a Narcissist. If you have any kind of an consistent, active feed back system, I've found most narcissists even well meaning feedback that is designed to improve their performance. The thin skin and blaming show up very early, at which time you get rid of them at the first opportunity.
