Sibling relational aggression: Developmental change and associations with family relationships across adolescence.

Sibling relational aggression is an understudied social and family process that is of developmental significance in adolescence, a period of interpersonal relationship development. This study examined developmental change in sibling relational aggression across adolescence and used multilevel actor-partner independence models to test its longitudinal associations with mother-adolescent, father-adolescent, and sibling relationship qualities. Participants were 196 adolescent (firstborn-secondborn) sibling pairs from predominantly White families who averaged 16.47 years ( = .80) and 13.88 years ( = 1.15) of age, respectively, at baseline. Data were collected separately from each sibling during home interviews at three timepoints, each spaced a year apart. Longitudinal growth modeling revealed declines in sibling relational aggression from early to late adolescence. Findings from longitudinal multilevel actor-partner independence models revealed a negative within-person (WP) effect of father-adolescent intimacy and a positive WP effect of father-adolescent conflict on sibling relational aggression: On occasions when adolescents reported lower intimacy or more conflict with their fathers than usual (compared to individuals' own cross-time averages), adolescents reported experiencing more sibling relational aggression than usual. A between-person (BP) effect of mother-adolescent conflict also indicated that the cross-time average of mother-adolescent conflict was linked positively to the cross-time average of sibling relationship aggression. Primarily at the WP level, associations also emerged between lower sibling intimacy and higher sibling conflict and sibling relational aggression. For relationships with fathers and siblings, some effects were moderated by sibling structural characteristics. Discussion highlights the interplay of family relationship dynamics, including gender dynamics, and sibling relational aggression in adolescence. (PsycInfo Database Record (c) 2024 APA, all rights reserved).