Patterns of physical and relational aggression in a school-based sample of boys and girls.

The current study investigated the patterns of aggressive behavior displayed in a sample of 282 students in the 4th through 7th grades (M age = 11.28; SD = 1.82). Using cluster analyses, two distinct patterns of physical aggression emerged for both boys and girls with one aggressive cluster showing mild levels of reactive aggression and one group showing high levels of both reactive and proactive aggression. Both aggressive clusters showed problems with anger dysregulation, impulsivity, thrill and adventure seeking, positive outcome expectancies for aggression, and higher rates of bullying. However, the combined cluster was most severe on all of these variables and only the combined aggressive group differed from non-aggressive students on their level of callous-unemotional traits. Similar patterns of findings emerged for relational aggression but only for girls.