*Boutin S, Temcheff C.E, Déry M. (2020). The use of indirect aggression among boys and girls with and without conduct problems: Trajectories from childhood to adolescence. Journal of Abnormal Child Psychology.
Though conceptually distinct from other behavior problems, indirect aggression (IA) is correlated with physical aggression and is linked to oppositional defiant disorder and conduct disorder from childhood to adolescence. Thus, IA could be part of the clinical picture of children with identified conduct problems (CP). However, trajectories of IA have not been studied in children with CP. In the present study, we evaluated and compared the mean trajectory of IA from 7 to 14 years of age in children with (n = 328; 47.6% girls) and without (n = 320; 51.3% girls) early clinically significant CP using both parent and teacher ratings. We then examined if sub-groups of children distinguished themselves by their use of IA over time and tested for sex differences. Latent growth models showed that children with CP used IA at higher rates over time than children without CP. Regardless of this higher frequency, the use of IA in both groups of children was best described by down-turned curvilinear trajectories peaking at 10 years of age. Growth mixture models showed that children without CP, according to parent and teacher ratings, and children with CP, according to parent ratings, both followed two trajectories of IA over time, with, respectively, 10% to 14% of them following a high trajectory. As for sex differences, the use of IA of boys and girls without CP did not differ, but differences emerged for children with CP, with girls using IA more frequently. The clinical implications of the findings are discussed.