It has been suggested that
neurotrophins are involved in the etiopathogenesis of
attention-deficit/hyperactivity disorder (
ADHD). This study aimed to investigate whether there are differences in serum
brain-derived neurotrophic factor (
BDNF),
glial-derived neurotrophic factor (
GDNF),
nerve growth factor (
NGF), and neurotrophin-3 (NTF3) levels between children with
ADHD and healthy controls. A total of 110 treatment-naive children with the combined presentation of
ADHD and 44 healthy controls aged 8-18 years were enrolled in this study. The severity of
ADHD symptoms was determined by scores on the Conners' Parent Rating Scale-Revised Short and Conners' Teacher Rating Scale-Revised Short. The severity of depression and anxiety symptoms of the children were evaluated by the self-report inventories. Serum levels of
neurotrophins were measured using commercial
enzyme-linked
immunosorbent assay kits. The multivariate analysis of covariance (MANCOVA) revealed a significant main effect of groups in the levels of serum
neurotrophins, an effect that was independent of age, sex, and the severity of the depression and anxiety. The analysis of covariance (ANCOVA) indicated that the mean serum
GDNF and NTF3 levels of
ADHD patients were significantly higher than that of controls. However, serum
BDNF and
NGF levels did not show any significant differences between groups. No correlations between the levels of serum
neurotrophins and the severity of
ADHD were observed. These results suggest that elevated serum
GDNF and NTF3 levels may be related to
ADHD in children.