The association of ADHD and depression: mediation by peer problems and parent-child difficulties in two complementary samples.

Children with attention-deficit/hyperactivity disorder (ADHD) are at increased risk for the development of depression, with evidence that peer and academic difficulties mediate predictions of later depression from ADHD. In the present study, we hypothesized that parent-child relationship difficulties may be an additional potential mediator of this association. Academic, peer, and parent-child functioning were tested as mediators of the association of attention problems and depression in two distinctly different yet complementary samples. Study 1 was a cross-sectional sample of 5- to 10-year-old children (N = 230) with and without ADHD. Study 2 was a prospective longitudinal sample of 472 youth, followed prospectively from birth to age 20 years, at risk for depression. Despite differences in age, measures, and designs, both studies implicated peer and parent-child problems as unique mediators of depressive symptoms, whereas academic difficulties did not uniquely mediate the ADHD-depression association. Furthermore, inattention symptoms, but not hyperactivity, predicted depressive symptoms via the disruption of interpersonal functioning. The inclusion of oppositional defiant disorder into models impacted results and supported its independent role in parent-child problems. Implications include support for interventions that target interpersonal competence, which may effectively reduce the risk of depression among children with ADHD.