CRP and depressive symptom measurement: Additionally, Miller’s team found that depressive disorders with high inflammation (defined by CRP > 3 mg/L) constitute a distinct subtype, which display markedly different inflammatory marker levels from those with low inflammation (CRP ≤ 3 mg/L); they also have more pronounced core symptoms (e.g., anhedonia) and treatment characteristics (e.g., resistance to conventional antidepressants), and specific alterations in immune cell subtypes and molecular pathways, confirming the inflammation-related heterogeneity of depression (8).