This study aimed to evaluate the changes of BDNF in patients with depression and how it is affected by antidepressant treatment through meta-analysis.<h4>Methods</h4>Multiple databases (including PubMed, Embase and China National Knowledge Infrastructure (CNKI)) were searched for studies on BDNF levels in patients with depression published up to November 15, 2024. This evidence concerns the gene BDNF and depressive symptom measurement.