STAGE 3. Defining the population and objectives

What steps should be completed?

Step 1: Define the population


The classification of preventive interventions proposed in 1987 by the Institute of Medicine (USA) is now widely accepted in the field of drug addiction. This classification is based on the degree of vulnerability or exposure of the population to the risk factors against which the preventive intervention is directed. According to this classification, it is possible to distinguish between universal, selective and indicated prevention.

Universal prevention. This is aimed at the general population or sections of it (for example, the school population of 12 to 14 year-olds in a country or district), regardless of the different levels of vulnerability or exposure to risk factors of the individuals that make up the population that is the object of intervention. In universal prevention, it is assumed that all members of the population share the same general risk of substance use or abuse and that the entire population benefits to the same extent from preventive actions to prevent or delay the start of substance use.

Selective prevention. This is aimed at specific population groups defined by their increased vulnerability or exposure to risk factors (social, demographic, environmental, etc.) for substance use or abuse in comparison to their peers (for example,  juvenile offenders, youngsters who drop out of school, students who fail at school). Selective prevention programmes are aimed at the group as a whole, without considering the different risk levels of each individual within it. Its purpose is also to prevent or delay substance use or abuse in the target population.

Indicated prevention. This is aimed at individuals who use drugs, but who do not present dependence problems, or individuals with psychological or behavioural problems that can be predictive of future problematic drug use (for example, children or adolescents with dissocial behaviour or early aggression, children whose parents who do not fulfil their parental role). The objective of indicated prevention is not necessarily to prevent substance use but to prevent it from getting worse or becoming chronic, leading to drug dependence or other problematic forms of drug use.

This classification enables intervention objectives to be aligned more effectively to the needs of the population. In general terms, the intensity and requirements of indicated prevention strategies tend to be greater than selective prevention strategies which are, in turn, greater than universal prevention. Conversely, the relationship is reversed with respect to the number individuals accessed, with universal prevention reaching the most people.