A Dictionary of Psychological Medicine by Dr. Daniel Hack Tuke 1892

“HAIR OF THE INSANE. – Dr. Bucknill has said that a lunatic is a lunatic to his finger ends; he might have added, writes Darwin, ‘and often to the extremity of each particular hair.’ Although this is true, the indications of insanity which the hair affords are not great importance. The prevailing colour of the hair of the insane, there are grounds for supposing, is different from that of sane people of the same class in the same district. Those possessing hair of a black, dark, or dark brown shade, have a greater tendency to become insane than those having hair of a fair or light brown hue, and those having brown hair, neither very light nor very dark, have the least tendency any…

It is commonly believed that people with certain colours of hair are more prone to certain forms of insanity than others. It has long been recognised that black hair very often accompanies a melancholic temperament, and there is an impression that black-haired people are more liable to melancholia than light-haired, and that the latter are more subject to attacks of mania. Though our statistics confirm this impression the difference is not of a very striking nature. Esquirol believed that some people with dark hair and eyes became violently maniacal, and we have found that the percentage of dark-haired among the acutely maniacal is above the average. He also believed that the illness in the dark-haired terminated more frequently in a marked crisis, and that the fair haired fell more readily into chronic disease.

Grey hair is less common among the chronically insane who have become insane when young, and among the demented, owing partly to the fact that the cares and worries of life fall on them less, and are less felt. If, however, a person above middle age be attacked by insanity, greyness of hair rather tends to develop, whether recovery takes place or not, and in this respect insanity does not differ from many other diseases. Grief and fear are well known to turn the hair grey, and it is found that melancholia has a greater tendency to produce greyness than mania. Dr. Hack Tuke reports a case of recurrent insanity in which the hair turned grey during each attack, and recovered its healthy brown colour when the patient was well. Grey hair in the insane is very frequently found patchy.”

Reprinted from Tuke, D. Hack, A Dictionary of Psychological Medicine Giving The Definition, Etymology, And Synonyms Of The Terms Used In Medical Psychology,  with the Symptoms, Treatment, And Pathology Of Insanity And The Law Of Lunacy In Great Britain And Ireland.  (Edited by D. Hack Tuke, M.D., LL.D., Examiner in Mental Physiology in the University of London; Lecturer on Psychological Medicine At The Charing Cross Hospital Medical School; Co-Editor Of The “Journal Of Mental Science”), Volume I, London, J. & A. Churchill, 11 New Burlington Street, 1892, Pages 562, 563.