Tolerance is a physiologic process where the body adjusts to a medication that is frequently present. Usually higher doses of the same medication are required over time to achieve the same effect. It is a common occurrence for individuals to take high doses of opioids for extended periods. However this does not predict any relationship of misuse or addiction. A retrospective cohort study conducted in Australia found that the probability of further dispensing during the follow-up period remained very high if dispensing did not end in the first month. The quantity and the number of episodes of dispensing in the first month were significant predictors of the total duration of dispensing in the later period.