Functions of aggressive behavior and future functional impairment

•This study explored associations between subtypes of aggression and functional impairment.•Reactive physical aggression was associated with functional impairment.•Reactive relational aggression was not associated with functional impairment.

The present study investigated relations between proactive and reactive functions of physical and relational aggression and functional impairment across early childhood. It was hypothesized that reactive functions of aggression would be associated with functional impairment. Hypotheses with regard to proactive functions of aggression were exploratory. Participants were 36 children (22 girls) from a longitudinal study. At Time 1 (M = 50.31 months old, SD = 10.97), observations of aggressive behavior were collected during preschool free-play. At Time 2 (M = 73.33 months old, SD = 10.88), parent-report of functional impairment was collected. Reactive physical aggression was a significant and unique predictor of future impairment when controlling for gender and all other types of aggression. Implications of these findings are discussed from a developmental perspective.