They examined the range and levels of sibling aggression endured by the interviewees, observing measures such as:
- physical assault with and without a weapon or injury
- stealing something from the child with or without force
- breaking siblings' belongings on purpose
- saying things to make the child feel bad, scared, or unwanted
Outcomes revealed that sibling aggression during the previous 12 months was linked to significantly worse mental health for both teens and children. Distress was seen for children and teens who experienced severe and mild forms of sibling aggression.