Serum magnesium level in a sample of Egyptian patients with major depressive disorder: cross-sectional study

Abstract Background Major depressive disorder (MDD) is a prevalent mental health condition that manifests as profound emotional disturbances and considerable functional deficits. Magnesium (Mg), a vital mineral, plays a recognized role in numerous neuropsychiatric conditions, including depressive disorders. Nonetheless, the association between circulating Mg concentrations and MDD within the Egyptian demographic has yet to be definitively elucidated. This study aimed to evaluate serum Mg levels in MDD patients, assess their correlation with depression severity, and explore the diagnostic utility of serum Mg. Results The study included 30 newly diagnosed MDD patients and 30 healthy controls. Serum Mg levels were significantly lower in MDD patients (1.880 ± 0.190 mg/dL) compared to controls (1.996 ± 0.169 mg/dL, p = 0.015). An inverse relationship of notable strength was identified between serum magnesium concentrations and the severity of depressive symptoms, quantified using the Hamilton Depression Rating Scale (Ham-D17) ( r = − 0.592, p = 0.001). ROC curve analysis determined a serum Mg threshold of ≤ 1.8 mg/dL, yielding sensitivity and specificity rates of 46.7% and 80.0%, respectively, with an overall diagnostic accuracy of 67%. Conclusions A notable reduction in serum Mg levels was identified in individuals with MDD relative to healthy controls, and these levels correlated inversely with depression severity. Serum Mg may serve as a potential biomarker for MDD and its severity.