There's a difference, but it's not black and white, and I find it hard to imagine that most chemical addictions we know are bad enough in themselves to cause the extreme behavior that addicts exhibit.

Regardless, I was primarily thinking about the psychological side of addiction in the above post, and I think my point still stands. There are many examples of (almost) purely psychological addictions that people suffer from, and also in those cases I think it can be an interplay of habit formation, personality characteristics, and environment, that 'maintain' it, and not always 'deeper issues' (although I suppose one could consider environment a deeper issue...).