Magnesium and mood disorders: systematic review and meta-analysis

Background Magnesium (Mg2+) has received considerable attention with regards to its potential role in the pathophysiology of the mood disorders, but the available evidence seems inconclusive. Aims To review and quantitatively summarise the human literature on Mg2+ intake and Mg2+ blood levels in the mood disorders and the effects of Mg2+ supplements on mood. Method Systematic review and meta-analyses. Results Adherence to a Mg2+-rich diet was negatively associated with depression in cross-sectional (odds ratio = 0.66) but not in prospective studies. Mg2+ levels in bodily fluids were on average higher in patients with a mood disorder (Hedge's g = 0.19), but only in patients treated with antidepressants and/or mood stabilisers. There was no evident association between Mg2+ levels and symptom severity. Mg2+ supplementation was associated with a decline in depressive symptoms in uncontrolled (g = -1.60) but not in placebo-controlled trials (g = -0.21). Conclusion Our results provide little evidence for the involvement of Mg2+ in the mood disorders.