trajectory classes, respectively). Likewise, genotype was better able to discriminate between probabilities of membership in the low (GG = 73%, AG = 57%, AA = 32%) versus moderate (GG = 27%, AG = 32%, AA = 51%) decreasing trajectories among adolescents reporting high exposure to peer group antisocial behavior when compared with those reporting relatively little antisocial behavior within their peer group (GG = 82%, AG = 74%, AA = 72% versus GG = 12%, AG = 22%, AA = 24% in the decreasing low and moderate decreasing trajectory classes, respectively). Thus, an expected pattern of interaction effects emerges whereby the influence of CHRM2 genotype on longitudinal patterns of externalizing behavior appears to be stronger among adolescents whose peer networks display higher levels of antisocial behavior.
