I think most runners have an addictive personality. I know I do.
As William Glasser wrote in Positive Addiction, addictions can be positive. Or put another way, some addictions can be far less destructive than the behaviors the individual would pursue if not for the focus on the positive addiction.
For example, in the two years I couldn't run due to injury, I didn't turn to really negative addictions, like gambling, drinking, or overeating, but I did buy two motorcycles and a supercharged sports car. Looking back, I can see it was my need for an adrenaline rush that I was no longer getting from running.