Further Evidence for Family-Genetic Risk Factors in Attention Deficit Hyperactivity Disorder

TLDR

The study evaluated 140 ADHD probands, 120 controls, and 822 first‑degree relatives using blind raters and structured diagnostic interviews. Probands with ADHD had higher rates of conduct, mood, and anxiety disorders, and their relatives exhibited increased risks for ADHD, antisocial behavior, major depression, substance dependence, and anxiety, suggesting shared familial vulnerabilities and supporting distinct ADHD subtypes based on comorbidity.

Abstract

We examined 140 probands with attention deficit hyperactivity disorder, 120 normal controls, and their 822 first-degree relatives using "blind" raters and structured diagnostic interviews. Compared with controls, probands with attention deficit hyperactivity disorder were more likely to have conduct, mood, and anxiety disorders. Compared with relatives of controls, relatives of probands with attention deficit hyperactivity disorder had a higher risk for attention deficit hyperactivity disorder, antisocial disorders, major depressive disorder, substance dependence, and anxiety disorders. Patterns of comorbidity indicate that attention deficit hyperactivity disorder and major depressive disorders may share common familial vulnerabilities, that attention deficit hyperactivity disorder plus conduct disorder may be a distinct subtype, and that attention deficit hyperactivity disorder and anxiety disorders are transmitted independently in families. These results extend previous findings indicating family-genetic influences in attention deficit hyperactivity disorder by using both pediatrically and psychiatrically referred proband samples. The distributions of comorbid illnesses in families provide further validation for subgrouping probands with attention deficit hyperactivity disorder by comorbidity.