In a third step, analyses were further extended to include a set of three predictors (i.e., SNP, peer group antisocial behavior, and the SNP by peer group antisocial behavior product term) in a series of ten multivariate conditional growth mixture models, which were used to assess the interactive influence of gene by environment on probabilities of membership within discrete trajectory classes. Again, the interaction analysis was conducted only among those for whom genetic data were collected.
