Kurebayashi Yusuke, Otaki Junichi
Faculty of Nursing, Niigata University of Health and Welfare, 1398 Shimami, Kita, Niigata city, Niigata, Japan,
Psychiatr Danub. 2018 Jun;30(2):129-135. doi: 10.24869/psyd.2018.129.
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 brain-derived neurotrophic factor (BDNF) in patients with MDD to either establish or rule out this effect as a possible mechanism.
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.
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 (I=0%). The risk of bias was moderate.
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.
重度抑郁症（MDD）是世界上最常见的疾病之一，但通常对抗抑郁治疗具有难治性。然而，体育锻炼已被证明可改善MDD症状，尽管实现这一效果的机制尚不清楚。本系统评价和荟萃分析旨在阐明体育锻炼是否会增加MDD患者的脑源性神经营养因子（BDNF），以确定或排除这种作用作为一种可能的机制。
我们检索了五个电子数据库（PubMed、PsycINFO、CHINAL、Cochrane图书馆和日本医学中央杂志），以获取2017年10月24日前发布的干预性研究，这些研究考察了体育锻炼对MDD患者BDNF的影响，并将实验组与MDD对照组进行比较。符合纳入标准的研究进行荟萃分析，量化从基线到运动后BDNF的变化，采用标准平均差和随机效应模型。
五项研究符合条件，共纳入199名参与者。所有文章均纳入了症状严重的受试者；三篇文章研究了住院患者群体。所有文章均介绍了有氧运动。我们发现体育锻炼对BDNF水平没有显著影响（Z=0.32，p=0.75），且无异质性（I²=0%）。偏倚风险为中度。
我们得出结论，体育锻炼不会显著增加MDD患者的BDNF。因此，虽然BDNF升高已被证明对MDD患者有益，但体育锻炼可能通过不同的机制产生其益处。然而，纳入文章数量较少且缺乏多名评审人员增加了结果为假阴性的风险。
