Performance on the Wisconsin card-sorting test and serum levels of glial cell line-derived neurotrophic factor in patients with major depressive disorder

Introduction Some evidence suggests that neurotrophic growth factor systems might be involved in the etiology of major depressive disorder (MDD). Glial cell line-derived neurotrophic factor (GDNF) is a neurotrophic factor from the transforming growth factor-β family that plays a role in the development and function of the brain. This study aimed to test whether GDNF in serum was abnormal in MDD, and whether it was related to the cognitive impairment of MDD. Methods Serum GDNF levels in MDD patients (n = 32) and normal controls (n = 32) were measured with the enzyme-linked immunosorbent assay method. All subjects were assessed for performance on the Wisconsin card-sorting test (WCST). Results Performance on the WCST in MDD patients was significantly poorer than that in controls. Serum GDNF levels in MDD patients were significantly decreased compared to that of the control subjects (P < 0.001). Furthermore, the decrease in the serum GDNF levels positively correlated with performance in the WCST-% CONC and negatively with performance in the WCST-P in MDD patients. Discussion The findings suggest that MDD patients have extensive impairments of executive functioning, and lower serum GDNF might be involved in the pathogenesis of MDD, which may be associated with the cognitive dysfunction in MDD patients.