Decreased serum magnesium levels in depression: a systematic review and meta-analysis.

Background: Magnesium (Mg2+), an endogenous N-methyl-D-aspartate receptor antagonist, has received increased attention recently because of its role in the pathophysiology of and treatment response in depression. However, whether Mg2+ level is decreased in depression is not firmly established. We aimed to conduct a systematic review and meta-analysis to help making consensus for the association between Mg2+ levels and depression. Methods: A systematic search was conducted in the electronic database resources PubMed and Embase. After a careful selection of relevant studies, a meta-analysis using the random effects model was conducted in each measuring source, such as serum, plasma, and cerebrospinal fluid (CSF). Results: A total of 18 studies were included in this study. Among 11 studies that measured Mg2+ in the serum, Mg2+ level was lower in patients with depression than in controls (weighted mean difference  = −.088, 95% confidence interval  = −.164 to −.012). In the sensitivity analysis by removing studies one by one, 2 out of the 11 studies obliterated such significant differences. There were no significant differences in the Mg2+ levels in the studies for plasma and CSF. Conclusions: Despite some evidence supporting an association between decreased Mg2+ levels and depression from studies with serum, the results of our meta-analysis urge to use caution when associating Mg2+ levels and depression. Future studies are needed to establish a consensus for the role of low Mg2+ levels in depression. [ABSTRACT FROM AUTHOR]