School-based programmes to prevent alcohol, tobacco and other drug use.

Substance use and abuse are important public health problems in the USA and throughout the world. In many developed countries, the initial stages of substance use typically include experimentation with alcohol, tobacco, or marijuana with one's peer group during adolescence. While there have been gradual decreases in the use of these substances in recent years among youth in the USA and other countries, increases have been observed in the use and misuse of other substances, such as the misuse of prescription drugs and over-the-counter cough medications in the USA. From a developmental perspective, data shows that rates of alcohol, tobacco, marijuana, and other illicit drug use typically escalate during adolescence and peak during young adulthood, corresponding with the increased freedom and independence of this time of life. Substance use decreases for most young people as they take on adult responsibilities, although a proportion will continue or increase their use and develop substance use problems. Given what we know about the onset and progression of substance use, implementing preventive interventions during early adolescence is critical. Most drug prevention or education programmes take place in school settings. A variety of theory-based school-based drug prevention programmes have been developed and tested. The most effective programmes are delivered interactively and teach skills to help young people refuse drug offers, resist pro-drug influences, correct misperceptions that drug use is normative, and enhance social and personal competence skills. A key challenge is to identify mechanisms for the wide dissemination of evidence-based drug preventive interventions and ways to train providers to implement programmes effectively and thoroughly.