BDNF as a biomarker for successful treatment of mood disorders: a systematic & quantitative meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of clinical treatment and observational studies
PubMed 25553404 · doi:10.1016/j.jad.2014.11.044
What was done
A systematic review and meta-analysis evaluated peripheral brain-derived neurotrophic factor (BDNF) in healthy controls versus patients with major depressive disorder (MDD; 38 studies, n=6,619) and bipolar disorder (BD; 17 studies, n=1,447). Pre- and post-treatment BDNF concentrations were meta-analyzed by treatment response across 21 MDD studies (n=735) and 7 BD studies (n=88), comparing serum versus plasma measurements and assessing publication bias and heterogeneity.
What was found
Serum and plasma BDNF were decreased in acute MDD and acute BD compared to controls, with no significant difference during euthymia. Following antidepressant treatment in MDD, serum BDNF increased significantly in responders (Cohen's d = 1.27, p = 4.4E-07) and remitters (d = 0.89, p = 0.01), significantly more than in non-responders (d = 0.11, p = 0.69). Evidence was insufficient to meta-analyze plasma BDNF in MDD or treatment response in BD. Plasma effect sizes had higher variance than serum.
Why it matters
The findings support serum BDNF as a potential biological marker for successful antidepressant treatment response in MDD, demonstrating that peripheral BDNF recovery tracks clinical improvement rather than medication exposure alone.
Limits
Substantial between-study heterogeneity was only partially explained, and evidence of publication bias was found in serum studies. Data were insufficient to meta-analyze plasma BDNF response in MDD or treatment response in BD (limited to n=88 across 7 studies), and optimal measurement time points remain unestablished.
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