"The risk factors were stronger predictors of substance use outcomes compared to the protective factors, regardless of grade level or substance use type. In particular, the individual and peer risk factors were strongly related to lifetime and recent use of cigarettes, alcohol, and marijuana. Among the protective factors, the strongest associations with substance use were found in the community domain. Several age-related differences in the associations were also found, suggesting that family and community factors were more salient among younger grades whereas peer and school factors were stronger among older adolescents."

Source

Michael J. Cleveland, Ph.D; Mark E. Feinberg, Ph.D.; Daniel E. Bontempo, Ph.D.; and Mark T. Greenberg, Ph.D., "The Role of Risk and Protective Factors in Substance Use across Adolescence," Journal of Adolescent Health, (August 2008); 43(2): 157–164.
http://www.ncbi.nlm.nih.gov/p…