A set of multinomial regression models were performed using the measure of cannabis use/problem use as a three-category outcome. First, the univariate effect of each early-life predictor on this cannabis measure was assessed followed by adjustment for conduct problem trajectory. Secondly, the univariate effect of conduct problem trajectory on cannabis use/problem use was assessed, followed by adjustment for the same set of early-life predictors. Finally, to evaluate the possible public health importance of these childhood influences on adolescent cannabis use we estimated the population attributable risk fraction (PARF) associated with the factors associated most strongly and substantially with cannabis problems 24. All regression analyses were carried out in Latent Gold version 4.5.0.11145 25. For all models containing the conduct problems measure, a ‘three-step’ approach was followed in order to utilize the variable derived previously 10 but to adjust for the potential impact of classification error in this variable (for detail see Appendix).
