Association of Biomarkers with the Severity of Depression

The pathogenesis of depression remains elusive and uncertain. The literature suggests that low-grade systemic inflammation might contribute to the etiology of depression. Other markers that are studied are serum magnesium and serum cortisol. The association between these factors might help understand the etiology.

This was a cross-sectional study conducted on a sample of 40 participants. Socio-demographic data was noted, and the Hamilton depression rating scale was applied to rate the severity of depression. Blood samples were drawn at 8 a.m. to record a complete blood picture (to derive the neutrophil-lymphocyte ratio (NLR)), C-reactive protein, serum magnesium, and serum cortisol.

In this study, conducted on a sample size of 40, inflammatory markers such as C-reactive protein (CRP: mg/dl) and NLR were significantly increased to 15.52 ± 13.10 and 6.46 ± 2.92, respectively, showing an underlying inflammatory pathology. Serum cortisol (µg/dl) was also raised to 22.30 ± 5.46, and there was a fall in serum magnesium. Also, it is noteworthy that all these markers were significantly associated with the severity of depression, as the Pearson correlation between the Hamilton depression rating scale-21 item (HAM-D-21) score and CRP, NLR, and serum cortisol was positive and statistically significant (r = 0.55, p < .01; r = 0.51, p = .01; r = 0.46, p = .002). The Pearson correlation between the HAM-D score and serum magnesium was negative and statistically significant (r = -0.82, p < .01).

There is a state of systemic inflammation, hypercortisolemia, and hypomagnesemia in depressive disorders.