RESUMO
Adverse childhood experiences (ACEs) are associated with externalizing behaviors. Whereas some ACEs affect individual children (i.e., child-specific; e.g., failing a grade), others affect the family unit (i.e., family-wide; e.g., parent losing a job); effects of ACEs on externalizing behavior may manifest differently across groupings of ACEs. Moreover, birth order may modify the association between child-specific and family-wide ACEs and externalizing behavior due to differences in the experience of being a younger versus older sibling. This study examined the externalizing behavior of siblings in relation to their experiences of child-specific and family-wide ACEs to test the hypothesis that younger siblings are at greater risk for developing externalizing symptoms following familial ACE exposure. Participants were 61 sibling pairs (younger sibling Mage = 11.37 years, 44.1% male; older sibling Mage = 13.1 years, 52.5% male) recruited from six schools in the northeastern United States. Parents rated each child's externalizing behaviors (e.g., bullying, meanness) and retrospectively reported on each child's experience of 34 ACEs; two raters categorized ACEs as child-specific (n = 10) or family-wide (n = 24). Multilevel modeling revealed that both child-specific and family-wide ACEs were associated with increased externalizing behaviors. Birth order moderated the effect of family-wide (but not child-specific) ACEs on externalizing behaviors, independent of sex and age. Externalizing behavior was higher for younger siblings as compared with older siblings, particularly when a high number of ACEs (6+) were reported. This research should prompt future exploration of mechanistic theories of the impact of family-wide and child-specific ACEs and the role of birth order.