There are two important questions in regard to the relation between injuries to the head and insanity. First, Is trauma a true cause of insanity, i. e., can an injury alone, acting on a normal man of healthy ancestry who is not suffering from cerebral arterial disease, syphilis, alcoholism or any other disease which affects the brain or who has not been broken down by the mere stress of life, cause insanity, or is the trauma a mere exciting cause, a provocative agent, which acting on a man already predisposed and ready to become insane gives him an opportunity so to do? Second, Does any characteristic type of insanity follow trauma? From the mental symptoms alone, while ignorant of the history of an injury, is it possible in any given case to know that a man is insane because he has received a trauma?
As to the first question no
BURR CW. TRAUMA OF THE HEAD AS A CAUSE OF INSANITY.. JAMA. 1907;XLVIII(1):33-37. doi:10.1001/jama.1907.25220270033001f