I read quite a lot of autobiographies (business people, media), and pretty much all of them involve obsessive hard work. That's kinda why they're successful.
Not that I'm putting a stake into either side of this debate, but workaholism is clearly also extremely detrimental to your health; there are ways to abuse drugs while being careful about your health just like there are ways to work 70 hours a week and still take care of yourself --- it's just that in both cases people rarely pull it off.
shrug I think most workaholics are workaholics because they enjoy their work.