Survey to measure the effects of a drugs prevention program for pupils in final forms of primary schools. Attitude and knowledge about use of drugs / attitude of people around respondent (schoolmates, friends, parents etc.) to drugs / use of drugs by respondent now, in the past and intentions for the future / experimental group (took part in drugs prevention program): reminiscence to drugs prevention program / frequency of visiting pubs, disco's / criminal behaviour Background variables: basic characteristics/ household characteristics/ occupation/employment/ educatio