Prevalence and patterns of drug use among the general population, measured by probabilistic surveys of the adult and school population, is one of five EMCDDA key indicators that assess the drugs situation and allow monitoring of progress towards EU and Member State drug policy targets. Data from general and school population drug surveys provides basic information to help to understand patterns of use, risk perceptions, social and health correlates, and consequences of use of illicit drugs and other psychoactive substances.
To achieve their real value in policy terms, surveys should be repeated at regular intervals with a similar methodology in order to allow identification of changes in prevalence and patterns of use, with sample sizes large enough to allow analysis of main sub-groups of the population. Member States should aim to conduct a series of consistent nationally representative surveys of the adult, and school populations, with standard age groups. At a minimum, data should be reported on period prevalence (lifetime, last year and last month) of different drugs. Surveys of good quality and sufficient sample size can give rich information on patterns of use in different subgroups, but may underestimate drug use in certain hidden and/or vulnerable populations, and complementary methods will be necessary (targeted surveys, indirect methods).
For surveys conducted among the adult population in households, the EMCDDA Handbook for surveys among the general population reviews and discusses key methodological issues regarding drug population surveys and provides guidelines for reporting of information to the EMCDDA. The Handbook provides a list of core items, called the European model questionnaire (EMQ), for inclusion in questionnaires of national surveys, or for reporting equivalent data from existing surveys. The EMQ can be used to collect data on the period prevalence of a range of drugs, as well as information on age of first use and frequency of use.
Methods for representative school surveys may be found in internationally coordinated school survey projects, and several national projects in Europe and the United States. School surveys typically collect data in classrooms through anonymous questionnaires on the use of alcohol and a range of drugs. In school populations, the target age of students surveyed can substantially influence the results.
More information on the GPS key indicator can be found in the 'GPS toolbox' on this page.
The GPS toobox provides access to a range of GPS-related material developed by the EMCDDA over the years. New resources will be added as they arrive.