Brain-derived neurotrophic factor blood levels after electroconvulsive therapy in patients with mental disorders: A systematic review and meta-analysis

Objective: Multiple studies have indicated that electroconvulsive therapy (ECT) could increase brain-derived neurotrophic factor (BDNF) concentrations in patients with different mental disorders. The aim of this synthesis was to evaluate post-ECT BDNF concentrations in patients with various mental disorders.Methods: The Embase, PubMed and Web of Science databases were systematically searched for studies in English comparing BDNF concentrations before and after ECT through 11/2022. We extracted the pertinent information from the included studies and evaluated their quality. The standardized mean difference (SMD) with a 95% confidence interval (CI) was calculated to quantify BDNF concentration differences.Results: In total, 35 studies assessed BDNF concentrations in 868 and 859 patients pre and post-ECT treatment, respectively. Post-ECT-treatment BDNF concentrations were significantly higher than the pretreatment concentrations (Hedges'g = -0.50, 95% CI (-0.70, -0.30), heterogeneity I2 = 74%, p < 0.001). The analysis that combined both ECT responders and non-responders demonstrated a marked increase in total BDNF levels subsequent to ECT treatment (Hedges'g = -0.27, 95% CI (-0.42, -0.11), heterogeneity I2 = 40%, p = 0.0007). Conclusion: Irrespective of the effectiveness of ECT, Our study shows that peripheral BDNF concentrations increase significantly after the entire course of ECT, which may enhance our comprehension of the interplay between ECT treatment and BDNF levels. However, BDNF concentrations were not associated with the effectiveness of ECT, and abnormal concentrations of BDNF may be linked to the pathophysiological process of mental illness, necessitating more future research.