Predicting drug abuse: review and reformulation.

Current knowledge points to several psychosocial risk factors, each of which correlates with drug abuse but does not explain all of the variance. Predictive studies have shown that combinations of these risk factors predict drug abuse better than any single risk factor does, but no one combination reliably predicts better than any other. These findings suggest, as stress theory postulates, that number of risk factors predicts drug abuse better than any particular set of risk factors.