The cognition is a long journey for Traditional Chinese Medicine (TCM) too. It went through a few phases before what it looks now. Huangdi Neijing, also known as The Inner Canon of Huangdi or Yellow Emperor's Inner Canon, clearly pointed out that emotional factors could contribute to the onset of depression;

The Huangdi Bashiyi Nanjing, The Huang Emperor's Canon of Eighty-One Difficult Issues, came up with the pathogenic mechanism and key differences between mania and depression. It argued that a manic episode was characterized by abnormally high moods, noise, and disturbance while a depressive episode by down moods and apathetic facial expressions;

Zhu Danxi, the famous TCM doctor in the Jin and Yuan Dynasties, put forth a well-known theory of heart spirit confused by phlegm, which provided the direct theoretical ground to treat depressive episode by clearing phlegm; The Yi Lin Gai Cuo (Correcting the Errors in the Forest of Medicine), written by Wang Qing-ren in Qing dynasty, made a breakthrough by showing clearly the close connection between depressive phase and brain.

DIFFERENCE AMONG MANIA, DEPRESSION, AND BIPOLAR
As stated, depression are manifested by symptoms of depressed mood, indifference, anxiety, pessimism, silence, retardation, and incoherency, etc. while mania by symptoms of hyperactive spirit, anger, agitation, restlessness, raving, hitting people and destructing things, hyperactivity, and Irritability, etc. Among the patients, young adults are most susceptible to both while children and the eldly appear to be rare. In addition, these two phases are not entirely separated and could transform to each other easily, thus so called bipolar disorder in the case of violent mood swings.

There are two major basic patterns in TCM theory – access syndrome and deficiency syndrome. In the early stage most of them are excess types while thus mixed with access and deficiency in prolonged illness.

In depressive phase, access manifests as Qi depression, phlegm blocking, and blood stasis while deficiency as depletion of spleen Qi and heart blood in chronic case; In manic phase, access presents as fire stagnation, phlegm obstructing, and heat accumulation while deficiency as impaired yin in heart and kidney combined with hyperactivity of fire due to yin deficiency by failing intercourse between fire and water.

PRINCIPALS OF NATURAL REMEDIES
Since most are caused by excess pathogen in early stage, the treatments should give priority to regulate Qi flowing, relieve Qi stagnation, smooth spiritual mechanism, lower fire, eliminate phlegm, and remove blood stasis for resuscitation; Since most are induced by deficient vital Qi in late period, the preferred remedies should be benefiting heart and spleen, nourishing yin to tonifying blood, and coordinating yin and yang.