The misuse of alcohol, tobacco, and other drugs is a problem with seri
ous health and social consequences worldwide. The causes of this misus
e are complex and multifaceted. For an examination of these complex is
sues we must look to a variety of risk factors, from those that are bi
ological, to those that are psychological, social, and familial, and o
n to those that encompass the environment. Prevention research has sho
wn that successful prevention interventions are those which appropriat
ely target these factors in individuals at risk and overcome them by e
nhancing individuals' resiliency and providing them with protective fa
ctors. While several important and successful preventive interventions
have been identified, research is needed to refine these strategies a
nd identify how they achieve their effects, which are most appropriate
for youngsters at different developmental stages, and which are most
likely to sustain their effects over time.