The present study sought to describe and predict developmental profiles of externalizing problems longitudinally from childhood to adulthood using a developmentally-informed actuarial approach. Findings suggested that, on average, externalizing problems decreased from early childhood to preadolescence (ages 5–11), increased during adolescence (11–16), and decreased again from late adolescence to adulthood (16–27). There was considerable variability in the developmental trajectories of externalizing problems. We were best able to account for individuals’ trajectories with a quartic function. Further, many individual risk factors predicted the ending values at age 27 (intercepts) or the change over time (slopes) in externalizing problems. This affirms the theoretical and empirical basis for our selection of the risk variables. In a very broad sense, the findings replicate the prior research on factors in externalizing behavior problems. However, of course it would be expected that these risk factors have some degree of overlap. And in fact, when we combined the predictors into one model to test collective risk, fewer predictors remained associated with the ending values or slopes of externalizing problems, suggesting that the risk and protective factors accounted for overlapping variance in externalizing problems.
