Changes in prevalence of problem opiate use in Germany between 1990 and 2000

Estimates of opiate use are calculated for the years 1990/1991, 1995 and 2000 in order to explore the development of problem opiate use in Germany in the preceding decade.

The estimates stem from multiplier methods which extrapolate from a sample (benchmark) of known drug users to the total population by multiplying the benchmark by an appropriate factor that accounts for the unknown population. Data came from the German treatment monitoring system, police and mortality statistics.

The population estimates for 2000 resulted in 166,300-197,500 problem opiate users based on treatment data, 153,000-190,000 heroin users from police data, and 126,900-169,200 (current) injectors from mortality data. Recalculated estimates for 1990/1991 and 1995 derived from the same data sources were found to be somewhat lower.

The reported estimates between 1990 and 2000 point at a moderate increase of problem opiate users in the 1990s. The population estimates based on the multiplier method using three different data sources may be considered consistent for the highly overlapping target groups of (current) injectors, problem heroin and problem opiate users. Nevertheless, some of the applied multipliers are based on small-scale studies, raising the question of representativeness. National prevalence estimates may be improved by using other techniques such as multivariate indicator, capture-recapture, or dynamic models.