Neuroticism, Depressive Symptoms, and Serum BDNF

Objective: Animal models and clinical studies suggest that brain-derived neurotrophic factor (BDNF) is involved in the pathophysiology of depression. We test whether serum and plasma levels of BDNF are associated with trait neuroticism and its facets and with state measures of depressive symptoms. Methods: In a community-based cohort (N = 2099), we measured serum and plasma BDNF concentrations and administered the Revised NEO Personality Inventory and the Center for Epidemiological Studies Depression Scale. Covariates included age, sex, cigarette smoking, obesity, and antidepressant use. Results: Serum BDNF concentrations were inversely related to neuroticism (r = -0.074, p < .001), in particular the depression facet (r = -0.08, p < .001). Lower BDNF concentrations were also associated with severe depressive symptoms (Center for Epidemiological Studies Depression Scale >= 28; odds ratio - 0.906; 95% confidence interval - 0.851-0.965). The association of serum BDNF with neuroticism was independent of depressive symptoms, indicating that serum BDNF might represent a biological correlate of neuroticism and not just of transient depressive states. Plasma BDNF was not associated with measures of depression. Conclusions: Our study suggests that lower serum BDNF is associated with both a dispositional vulnerability to depression and acute depressive states in the general population.