Childhood irritability-aggression profiles and parent-to-child violence: Evidence of interactive effect in predicting youth violence.

Objective: Early irritability, aggression, and parent-to-child violence (PCV) each are presumed to predict later violent behavior. Few studies, however, have examined these factors simultaneously. This study investigated how irritability and aggression jointly manifested during childhood and whether such manifestations, PCV, and their interactions were associated with late-adolescent violence.

Method: A prospective sample of 900 participants (55.8 % girls; 55.7 % Black, 24.7 % White, 11.9 % mixed race, 7.7 % other race) from the LONGitudinal Studies of Child Abuse and Neglect (LONGSCAN) was followed from 4 to 18 years old. Caregivers assessed children's irritability and aggression biyearly (ages 4-12), and self-reported violence toward their children by age 12. Children reported their violent behaviors at age 18.

Results: Group-based dual trajectory modeling identified three profiles varying in the combined levels of irritability and aggression for both genders: Irritable and Aggressive profile, Irritable Only profile, and Typically Developing profile. Binomial logistic regression analyses showed an independent association of the Irritable and Aggressive profile with violence in boys. PCV was associated with violence only in boys with the Irritable Only profile. No such associations were found in girls.

Conclusions: Aggression manifested and persisted alongside irritability, but not vice versa during childhood. Comorbidly aggressive and irritable boys had an increased risk of violence, and irritable boys did so only when exposed to PCV. These findings suggest the gender-specific roles of irritability and aggression in portending violent antisociality, and indicate the need to address these problems in conjunction with violent parenting for preventing youth violence.