Association Between Serum Magnesium Levels and Suicidal Behavior in Patients Diagnosed With Depression: A Cross-Sectional Case-Control Study

BACKGROUND: Depression is a common psychiatric illness characterized by persistent low mood, anhedonia, and reduced energy. Severe forms of depression are associated with increased risk of suicidal behavior. Emerging evidence suggests that micronutrient imbalances, including deficiencies in magnesium, vitamin D, zinc, and B-complex vitamins, may influence neuropsychiatric functioning by affecting neurotransmitter synthesis, neuroinflammation, and synaptic plasticity, thereby impacting mood regulation. Methodology: This cross-sectional observational study was conducted at a government medical college in Madhya Pradesh. A total of 200 patients attending the psychiatry outpatient department were enrolled: 100 diagnosed with major depressive disorder and suicidal behavior (case group), and 100 age- and sex-matched patients with depression but without suicidal behavior (control group). Depression severity was assessed using the Hamilton Rating Scale for Depression (HAM-D), and suicidal behavior was evaluated using the Revised Suicidal Behavior Questionnaire (SBQ-R). Ethical approval and informed consent were obtained prior to participation. Results: The mean serum magnesium level was significantly lower in the case group (1.59 ± 0.19 mg/dL) compared to the control group (1.90 ± 0.10 mg/dL, p < 0.001). In both groups, magnesium levels decreased as the severity of depression (measured by the HAM-D scale) increased. A statistically significant negative correlation was found between serum magnesium levels and suicidal behavior scores (SBQ-R) in the case group (r=-0.612, p<0.001). CONCLUSION: The findings of this study indicate that lower blood magnesium levels are associated with more severe depression in both study groups. Measuring serum magnesium levels at the time of diagnosis may aid in providing more personalized treatment plans. Additionally, magnesium supplementation could be explored further as an adjunct strategy to reduce depressive symptom severity and suicidal behavior risk.