It depends on the addiction, really. You could be addicted to reading, which isn't bad at all. You could be addicted to anime or manga, which again, isn't bad, I don't think. But you could be addicted to soda, which is bad for your health and teeth. You could also be addicted to nicotine or tobacco..which isn't healthy either. It's actually fatal if it goes too far. So it depends on the addiction, and how you treat it. But if you treat it, then it isn't much of an addiction now, is it?