Case report

https://doi.org/10.24869/psyd.2018.129

DOES PHYSICAL EXERCISE INCREASE BRAIN-DERIVED NEUROTROPHIC FACTOR IN MAJOR DEPRESSIVE DISORDER? A META-ANALYSIS

Yusuke Kurebayashi ; Faculty of Nursing, Niigata University of Health and Welfare, Niigata, Japan
Junichi Otaki ; Faculty of Health Sciences, Kyorin University, Tokyo, Japan

Abstract

Background: Major depressive disorder (MDD) is one of the most common disorders in the world, but is generally refractory to
antidepressant treatment. However, physical exercise has been demonstrated to improve MDD symptoms, though the mechanism through
which this is achieved is not clear. This systematic review and meta-analysis aimed to clarify whether physical exercise increased brainderived
neurotrophic factor (BDNF) in patients with MDD to either establish or rule out this effect as a possible mechanism.
Subjects and methods: We searched five electronic databases (PubMed, PsycINFO, CHINAL, Cochran Library, and Japanese
Central Review of Medicine) for interventional studies released prior to 24 October 2017, examining the effects of physical exercise
on BDNF in patients with MDD that compared the experimental group with an MDD control group. Those studies meeting the
inclusion criteria were subjected to a meta-analysis in which changes of BDNF from baseline to post-exercise were quantified, with
a standard mean difference and random effect model.
Results: Five studies were eligible and included 199 participants. All articles included subjects with severe symptoms; three
articles studied inpatient populations. All articles introduced aerobic exercise. We found no significant effect of physical exercise on
BDNF levels (Z=0.32, p=0.75), and no heterogeneity (I2=0%). The risk of bias was moderate.
Conclusions: We conclude that physical exercise does not significantly increase BDNF in patients with MDD. Thus, while
increased BDNF has been shown to be beneficial in patients with MDD, physical exercise likely produces its benefits through a
different mechanism. However, the small number of included articles and lack of multiple reviewers increase the risk of the result
being a false negative.

Keywords

BDNF; MDD; depression; antidepressant; meta-analysis

Hrčak ID:

202055

URI

https://hrcak.srce.hr/202055

Publication date:

26.6.2018.

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