Exploratory study to evaluate plasma vasopressin and apelin-13 levels in children with attention-deficit hyperactivity disorder.

AIM Vasopressin exerts robust influences on social communication and behavior in humans. Apelin is a relatively novel neuropeptide that could counteract vasopressin's actions and has been shown to be closely related with a broad range of physiological functions. Abnormalities in vasopressin and apelin have been detected in a variety of psychiatric disorders, but their relation to attention-deficit hyperactivity disorder (ADHD) is unknown. In the present study, we explored the plasma levels of vasopressin and apelin-13 in children with ADHD. METHODS Thirty-four children with ADHD and 36 healthy controls were enrolled in this study. The severity of ADHD symptoms was assessed via Conners' Parent Rating Scale and Conners' Teacher Rating Scale. Plasma levels of vasopressin and apelin-13 were measured using commercial enzyme-linked immunosorbent assay kits. RESULTS The mean plasma apelin-13 levels were significantly higher in male children with ADHD than in male control subjects; no significant difference was found between the groups for plasma apelin-13 levels in girls or in the entire subject cohort. Plasma vasopressin levels did not show any significant differences between groups. There were no significant correlations between plasma levels of these neuropeptides and scores for Conners' Parent Rating Scale and Conners' Teacher Rating Scale. CONCLUSION Our results suggest a sex-specific association between plasma apelin-13 levels and ADHD. Apelin-13 may play a role in the etiopathogenesis of ADHD either with a direct impact on the apelin receptor or via its opposing effect on the vasopressinergic system.