Middle school addictive behavior involvement is highly predictive of future dysfunction. We tested whether a set of high-risk personality traits, measured in elementary school, predicted drinking, smoking, and binge eating in middle school. We studied 1,906 children in two waves: Wave 1 was the last year of elementary school and wave 2 was the first year of middle school in the participating schools. In a design controlling for sex, pubertal status, prior engagement in addictive behaviors, and other high-risk personality traits, we found that (a) fifth grade urgency, the tendency to act rashly when emotional, predicted drinking, smoking, and binge eating during sixth grade; and (b) fifth grade low conscientiousness, which reflects a failure to plan ahead or persevere on tasks, predicted drinking and smoking during sixth grade. It appears that high-risk middle school addictive behavior can itself be predicted from individual differences present in elementary school. Implications for future research and prevention are discussed.