Success or failure of drug abuse prevention in the school environment? A meta-analysis of the programs in Spain

The present study describes the results of a meta-analysis of the effectiveness of drug abuse prevention programs within the school setting in Spain. Twelve research reports appeared between 1985 and 2002, which fulfilled the selection criteria, were identified leading to 21 independent studies. The overall effect size revealed that prevention programs against drug abuse at school are effective, though their effectiveness is small (d+= 0.20). However, effectiveness increases until it reaches a moderate level (d+= 0.65) at medium-term follow-up (range: 6 – 18 months). The programs proved to be more effective with alcohol, than with tobacco or other drugs. The programs were more successful in reducing drug use and improving knowledge than in changing attitudes towards drugs. The most effective component of the programs was providing information about substances. These findings and some suggestions for future research are discussed.