Abstract

Estimates of the size of the population of high-risk drug users (HRDU) are needed for planning services. The focus has traditionally been on young adults in their 20s and 30s. However, treatment services in Greece are encountering a rapidly increasing number of older users, chiefly heroin users, who were young adults in the 1980s and 1990s when the drug use epidemic was growing. We apply capture-recapture techniques to data from 2004-2013 to estimate the "hidden population" of older users who did not seek treatment in a given year, in order to estimate the numbers of HRDU in the 50-59 and 60+ age groups. These may already represent 10% of the total and are expected to continue to increase substantially as the HRDU population ages, with important implications for service provision.