Evidence of familial association between attention deficit hyperactive disorder and major depressive disorder in probands of ADHD (September 2003- march 2004)

Background&Objective: Comorbidity between ADHD (Attention Deficit Hyperactivity Disorder) and major depression has been reported from both epidemiologic and clinical studies of both children and adults. With the use of family study methods, we tested hypotheses about patterns of familial association between attention deficit hyperactivity disorder (ADHD) and depressive disorder among first-degree relatives of clinically referred children and adolescents with ADHD. Materials&Methods: In this case – control study, were 208 probands with ADHD (aged 5-17 yrs) were diagnosed by clinical interview and the Schedule for Affective Disorders and Schizophrenia for School–Age Children Present and Lifetime version (K–SADS–PL), and they were assessed for major depression with interview and K- SADS. 779 first degree relatives (416 parents, 363 siblings) were assessed with interview and K- SADS (for under 18 yrs) and SADS (for age up to 18 yrs) and Wender (for age up to 18 yrs) for major depression and ADHD. Results: Familial risk for ADHD was similar in the relatives of the ADHD probands. The risk for major depression disorder was three times higher in relatives of probands who had ADHD with depressive disorder than in those of the ADHD probands without depressive disorder. There was a tendency for ADHD probands' relatives who themselves had ADHD to have a higher risk for depressive disorder than ADHD probands' relatives who did not have ADHD (cosegregation). Conclusion: These findings are consistent with the hypothesis that ADHD and major depression disorder cosegregate within families