Some people are seemingly 'addicted' to their work and by doing work itself, almost to the point of precluding all other activities and interactions (usually social). By this question, I mean when people go beyond a 'passion' for the work, into an almost obsessive approach. (I have met a few people like this).

Is this addiction to work similar to other addictions? or is there something else triggering this almost obsessive work-ethic to the preclusion of almost all other activities?

I am after peer-refereed articles about any studies that have been performed on this.