To some extent, melancholia in different Traditional Chinese Medicine (TCM) Syndromes represents different “subtypes” of melancholia. Whether bipolar depression or general melancholia, whether accompanied with or without psychotic symptoms, or with or without cognitive impairment, there are clinical and possible biological differences in these melancholia, which indicates that different “subtypes” of melancholia represented by different TCM syndromes not only are different clinical syndromes, but also imply that there may be some biomarkers. The melancholia with liver depression and stagnation is different from melancholia with deficiency of both heart and spleen in clinical symptoms, which may indicate that there are differences in some potential biological biomarkers. For example, central nervous transmitters, trace elements, electrophysiology, neuroendocrinology, brain imaging, and even genomics may differ among different TCM syndrome types of melancholia, which not only serves for the modernization of TCM, but also finds biological differences for different TCM syndrome types of melancholia.

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