Association of low serum BDNF with depression in patients with Parkinson's disease

Increasing evidence shows that brain-derived neurotrophic factor (BDNF) plays a critical role in the development of depression and the mechanisms of antidepressant. Parkinson disease (PD) is associated with depression and decreased BDNF. The aim of the present study was to examine the association of BDNF with depression in PD, which has not been investigated.

We recruited 96 PD patients with (n = 46) and without depression (n = 50) and 102 healthy controls and measured the serum BDNF levels in both groups. Zung Self-Rating Depression Scale (SDS) was administered for the severity of depression and Hoehn-Yahr staging scale for motor abilities in PD patients.

Serum BDNF levels were significantly lower in PD patients than healthy controls (p < 0.01). Also serum BDNF levels were significantly decreased in PD patients with than without depression (p < 0.01). BDNF levels were negatively associated with SDS in both PD patients with and without depression (both p < 0.01). Multiple regression analysis confirmed that in either PD with or without depression group, BDNF was an independent contributor to SDS (both p < 0.05).

Our findings suggest that decreased serum BDNF may be involved in the pathophysiology of depression in PD patients.