Traditional Chinese Medicine has associated FEAR with Shen Zangfu (related to Kidney function) for more than 2000 years.

A recent programme on the BBC entitled Incredible Medicine explores the medical history of a number of people who are beyond the range of what might be described as normal.

In Episode Two a person is featured who has absolutely no fear. He had a normal fear response until the removal of his Adrenal glands. These glands are associated with the Kidneys and thus, in TCM terms, with what is referred to as Shen Zangfu.
Incredible Medicine: Dr Weston's Casebook.

TCM has a long history of understanding the emotional causes of disease, and the treatment of conditions which have an imbalance of a particular emotion as the presenting main complaint.

It is interesting to see that Western Medical research is now becoming aware of some aspects of human functioning that have been known about by Chinese Medicine for millennia.