The drug acquisition curve: a method for the analysis and prediction of drug epidemiology

A method is presented to chart how a group acquires exposure to a drug. The resulting drug acquisition curve has a number of different parameters that describe the group's drug involvement. Key parameters include: (1) the age of exposure when the group begins to use the drug in greater numbers, probably because of exposure to drug-using peers; (2) the acquisition rate, the percent of the group who are newly exposed each year, a rate that is surprisingly constant over as much as 5 years; and (3) the asymptote, establishing the total percent of the group who will eventually try the drug. Acquisition curves for sequential age cohorts show changing trends in these parameters and can also be used to predict future drug epidemiology. A 4-year prediction based on this method proved to be very accurate for two of three drugs. For the third drug, a large increase in use was predicted, but the increase was even greater than expected.