Association between serum levels of glial cell line-derived neurotrophic factor and inattention in adult patients with attention deficits/hyperactivity disorder.

Glial cell line-derived neurotrophic factor (GDNF) may play an important role in attention. We investigated the association between serum GDNF levels and clinical status in unmedicated adults with attention deficit/hyperactivity disorder (ADHD) (n = 16) and healthy controls (n = 33); the levels were comparable between the ADHD and control groups (107.2 ± 31.7 vs. 110.5 ± 40.0 pg/mL, respectively; p = 0.77). In the ADHD group, higher GDNF serum levels were associated with severe subjective inattention (r = 0.528, p = 0.035). These preliminary results suggest that the serum GDNF level may not be a suitable biomarker for adult ADHD, although it may be associated with the pathophysiology of persistent inattention in adult ADHD.