Longitudinal findings from a Norwegian case-cohort study on internalizing problems in children with congenital heart defects.

To examine the association of the severity of congenital heart defects (CHDs) with internalizing problems in 18-month-olds and to explore the extent to which the internalizing problems are influenced by maternal distress and emotional reactivity in the child at age 6 months.We linked prospective data from the Norwegian Mother and Child Cohort Study, conducted by the Norwegian Institute of Public Health, with a nationwide CHD registry and identified 198 18-month-olds with CHDs in a cohort of 47 692 toddlers. Maternal reports on the children's emotional reactivity at age 6 months, the children's internalizing problems (anxiety, sleep problems, emotional reactivity) at age 18 months and maternal distress were assessed by questionnaires.We found an association at age 18 months between the severity of the CHD and anxiety but not sleep problems or emotional reactivity. Children with severe but not with mild or moderate CHDs were twice as likely to experience the symptoms of anxiety compared with controls. These symptoms are not merely sequelae of earlier psychological reactions or concurrent maternal distress.Should these findings be replicated, future studies ought to investigate the mechanisms leading to elevated anxiety in toddlers with CHDs. In addition, clinical interventions should address the child's anxiety as well as the interaction between the parents and the child.