Oxycontin/Oxycodone is an opiate and are two of the most highly addictive meds out there today. That's why there's so much crime associated with its' use. The withdrawal symptoms are very severe and most can't cut it without medication to lessen those symptoms.
Users of this drug do not sleep but a couple of hours at a time if at all. It produces a chemical in the brain that replaces what we would normally produce ourselves and in addicts of this kind, once the drug replaces this chemical, the body stops making the natural chemical, thus the constant need for more once each dose wears off. Once the dose begins to wear off, the brain craves this chemical to the point of desperation to get more as they become sicker and sicker. In the interim, the user will behave irratically and the range of actions can go from rage to mild mannered in a matter of a few minutes, once they put that next pill into their system. It's a very dangerous drug and beyond me how it got to be popular as a recreational drug.