Decreased serum levels of adiponectin in adult attention deficit hyperactivity disorder.

The main aim of this study was to investigate serum levels of adiponectin in adult patients with attention deficit hyperactivity disorder (ADHD). The second objective was to examine the effects of rare missense mutations in T-cadherin, an adiponectin receptor encoded by the ADHD candidate gene CDH13, on serum adiponectin levels. Total and high molecular weight (HMW) adiponectin levels were measured by an enzyme-linked immunosorbent assay in 44 patients and 29 controls. We found decreased serum adiponectin levels in ADHD patients. In a logistic regression model, adjusting for confounding by age, body mass index, and gender, HMW adiponectin and its ratio to total adiponectin were significantly associated with ADHD. In partial correlations, HMW adiponectin and its ratio to total adiponectin were significantly inversely correlated with self-reported psychiatric symptomatology. A non significant trend for higher levels of total adiponectin was observed in patients carrying CDH13 missense mutations compared to patients with wild type CDH13. The association of CDH13 mutations with adiponectin levels should be investigated in larger studies. This study shows that ADHD patients have decreased serum adiponectin levels, which are inversely correlated to psychiatric symptoms, suggesting a possible involvement of adiponectin, in particular the HMW form, in the pathophysiology of ADHD.