Drug users in prison — an overview of the methods and definitions used

National routine information on drug use and patterns of use amongst prisoners is rare. Most of the data available in the EU come from ad-hoc studies amongst prisoners, carried out at local level, with samples that vary considerably in size and they are often not representative of the whole prison system. This makes extrapolation to a national figure for the prison system very difficult. Furthermore, the lack of repeated surveys impedes trend analysis in most of the EU countries.

The data presented here come from a range of sources, which are often not comparable in terms of the methods used. Variations across countries and across surveys make comparisons between and within countries difficult, and are related to issues such as: sampling strategy; sample size; geographical coverage; population selection (for example, convicted/remanded, male/female); method of measurement of drug use (self-report, medical assessment). Moreover, studies in different countries use different measures of prevalence (lifetime or last year or last month prevalence), and frequency of drug use.