Are variations in whole blood BDNF level associated with the BDNF Val66Met polymorphism in patients with first episode depression?

Brain derived neurotrophic factor (BDNF) seems to play an important role in the pathophysiology of affective disorders. The current study investigated whether blood level BDNF is correlated with the severity of depressive symptoms and recent (six months prior to onset of depression) experience of stressful life events (SLE) in a cohort of patients with a first depressive episode. 262 patients with first episode depression (females 174, males 88, age range 18-70, mean age 41) participated and control sample of 84 participants was included (females 52, males 32, age range 22-70, mean age 42). Symptomatology was rated using Hamilton Rating Scale for Depression (HAMD-17) and Becks Depression Inventory (BDI 21). No differences in whole blood BDNF was seen in relation to the BDNF Val66Met polymorphism and no significant correlations between whole blood BDNF and HAMD-17 or BDI 21 scores were found. No significant associations between the experiences of SLE before onset of depression and BDNF level were observed. Finally, peripheral BDNF differentiated between patients and healthy control persons. In the current sample of first episode depressed patients, the Val66Met polymorphism was not associated with whole blood BDNF and whole blood BNDF level was not associated with the experience of recent SLE.