Sibling rivalry is normal. Fights between sisters and brothers are so common that they’re often dismissed as just part of growing up. But a recent study from the University of New Hampshire finds that sibling aggression is associated with increased depression and anxiety in children.

Although physical and emotional aggression by peers is generally thought to be more serious than by siblings, the present findings showed no independent effects. That is, the results of those experiencing persistent and unmonitored aggression, whether from siblings or peers, did not differ.  […]