Serum level of brain-derived neurotrophic factor in fibromyalgia syndrome correlates with depression but not anxiety.

Brain-derived neurotrophic factor (BDNF) has been known to play a role in fibromyalgia syndrome (FMS) patients. Depression and anxiety are quite common additional symptoms in FMS. However the role of BDNF in these symptoms still needs to be elucidated. Although BDNF has been shown to be relevant in major depression, however studies could not show such differences between FMS patients with and without major depression. As mood-related symptom occurs frequently and differs in its intensity in FMS patients, BDNF level should be measured in subgroup regarding depression and anxiety scale. Therefore the aim of this study was to evaluate the correlation of BDNF in serum of FMS with intensity of depression and anxiety. Additionally, interleukin (IL)-6 was measured. This study showed that serum level of BDNF was age-dependent in HCs. FMS patients had higher level of serum BDNF as compared to HC. Additionally, serum level of BDNF showed correlation with depression, but not with anxiety. Serum level of BDNF increased with depression score in FMS. However, serum level of IL-6 was not correlated with both depression and anxiety scores. Taken together, BDNF is involved in the pathophysiology of FMS. Additionally, it seems to be correlated with intensity of depressive symptoms in FMS.