What role does BDNF play in Stress?

BDNF (Brain-Derived Neurotrophic Factor) is a key protein for neuronal survival, growth, and synaptic plasticity, especially in the hippocampus. Under acute stress, BDNF levels may transiently rise to facilitate adaptive responses. However, chronic stress consistently downregulates BDNF expression, contributing to hippocampal atrophy and increased vulnerability to anxiety and depression. This link is supported by strong human evidence, including postmortem studies, neuroimaging, and genetic association research. The Val66Met polymorphism in the BDNF gene modulates stress sensitivity, with Met carriers showing greater stress-induced reductions in hippocampal volume. Lifestyle interventions like exercise and omega-3 intake can upregulate BDNF, offering potential resilience. Despite robust mechanistic understanding, clinical use of BDNF as a stress biomarker remains limited due to poor correlation between peripheral and central levels. Evidence grade: human-strong. Caveat: individual responses vary; BDNF is one factor among many in the stress response network.