1989; Kumpfer, 1989; Brook and Brook, 1990; Swaim, 1991; Clayton, 1992; Glantz and Pickens, 1992; Hawkins et al., 1992; Petraitis et al., 1995).
Protective factors are variables that are statistically associated with reduced likelihood of drug use (see Garmezy, 1983; Rutter, 1983; Brook et al., 1986a; Labouvie and McGee, 1986). In statistical terms, a protective factor moderates the relationship between a risk factor and drug use or abuse, or it buffers the impact of risk factors on the individual. When the protective factor is present, it is assumed that there will be considerably less drug use or abuse than would otherwise be expected, given the risk factors that are also present. Recent research has described two types of protective factors that could operate among adolescents (Brook et al., 1990). In the first type of protection (risk-protective), risk factors are attenuated by protective factors in the adolescent's personality. The second type of protection (protective-protective) involves a synergistic interaction whereby one protective factor potentiates the effects of another, so that their joint effect is greater than the sum of either protective factor considered alone.
One of the goals of etiologic research has been to identify variables (such as risk and protective factors) that may be associated with drug use. The underlying interest in such variables is to determine if manipulation of risk and protective factors can moderate drug use outcomes. For either a risk factor or a protective factor to be targeted in intervention efforts, however, it is first necessary to demonstrate that the variable is amenable to manipulation and can be influenced by changes in the environment or by educational or medical interventions. Finally, intervention efforts must be carried out as well-controlled, rigorous experiments for the analysis of results to be meaningful.
Over the past 25 years, progress has been made in understanding risk factors associated with drug use, including biological, psychosocial, and contextual (social and environmental) risk factors. Unfortunately less is known about protective factors. The accomplishments noted below are representative of advances in the field and are not meant to document all risk factors or protective factors that have been identified. Finally, this chapter is not meant to be exhaustive, but to illustrate the types of studies that have illuminated knowledge in this field and to highlight opportunities for further study.