Table 5.

A summary of best performing biomarkers in diagnosing major depressive disorder in adults

Category	Biomarkers	Medicationnaive	AUC	Sensitivity/specificity (%)	Key findings
Blood (Genomics)	MYT1	N	0.973	0.96/0.85	Decreased levels indicate reduced neurogenesis
Blood (Metabolomics)	Dopamine, GABA, Tyramine, Kynuramine	N	0.968	94.1/98.0	Decreased levels indicate reduced dopamine circulation
Neuroimaging/Neurophysiology	5-HT1A autoreceptor binding in dorsal/median raphe	Y	0.934	94.0/1.0	Increased binding indicates decreased serotonin circulation
Urine	Albumin, AMBP, HSPG, and APOA1	N	0.914	90.5/92.9	Increased levels indicate increased MDD- associated dyslipidaemia
CSF	NSE	N	NSE=0.820	NSE=81.0/75.0	Increased levels indicate increased neuronal cell loss
Combined - Blood and CSF	miRNA of Peripheral Mononuclear Blood Cells (PMBC) - miR-221-3p, miR-34a-5p, Let-7d-3p, miR-451a	N	miR-221-3p=0.940	miR-221-3p=93.8/90.5	Decreased levels of BDNF-associated miRNA indicate reduced neurogenesis
			miR-34a-5p=0.980	miR-34a-5p=96.9/95.2
			Let-7d-3p=0.970	Let-7d-3p=90.6/90.5
			miR-451a=0.940	miR-451a=84.9/90.5

AUC, area under the curve; N, no; Y, yes; GABA, gamma-aminobutyric acid; CSF, cerebrospinal fluid; NSE, neuron specific enolase; MDD, major depressive disorder; miRNA, microRNA