There are so many factors that determine how quickly or if ever a person becomes addicted. The simplest answer is that some people take the pills for recreational use, not for legitimate pain. Some people who have legitimate pain take them with good intentions until it becomes out of control and they become dependent upon them. Many addicts are probably predisposed to addiction meaning it's hardwired in their system and they have a very difficult time quitting. Not sure why you're asking, but if you have doubts, chances are you may already be addicted. Talk to your doctor and voice your concern.