[Reprinted from The Medical News, April i, 1893.] 
INSANITY IN TWINS. 
BY FRANK PARSONS NORBURY, M.D., 
ASSISTANT PHYSICIAN, ILLINOIS CENTRAL HOSPITAL FOR THE INSANE. 
JACKSONVILLE, ILL. 
A, M. and I. M., twin brothers, aged thirty-two years, 
natives of Prussia, not married, were admitted to the 
Illinois Central Hospital for the Insane, September 5, 
188—. The cause of the insanity, in each case, accord- 
ing to the verdict of the jury, was “self-abuse and loss 
of money.” Heredity was the real underlying cause, as 
their mother was insane. Masturbation seemed to us 
to have no etiologic importance in either case. The 
cases presented symptoms almost identical. A. M. had 
been insane two weeks before admission to the hospital, 
his attack beginning suddenly with maniacal excitement; 
he became very noisy and violent at times. The delu- 
sions, manifested then and since, were of a religious 
character, more or less systematized. He believed his 
brother was the Messiah, and had descended from 
heaven ; that the Messiah (his brother) had ordered that 
he be worshipped in sackcloth and ashes, and that, as a 
religious rite, A. M. should drink salt-water. When 
admitted to the hospital he was agitated, sleepless, 
emaciated, and would not take nourishment readily. 
After the agitation had subsided, he ceased to be violent, 
but the delusions were as persistent as ever, and became 
more systematized. He talked less, and after a time he 
settled into a state of indifference and carelessness, which, 
after two years, is practically unchanged. He has twice 2 
escaped from the hospital, both times going to his home, 
where he caused consternation by his insane actions. 
At present he is in good physical health, his mental 
symptoms being those of degenerative paranoia. 
I. M. did not become disturbed until a week after his 
brother’s insanity had developed, when suddenly he, 
too, became noisy and went about proclaiming that he 
was the Messiah, and the day of judgment was at hand. 
His agitation rapidly developed into violent maniacal 
excitement, necessitating restraint. When admitted to the 
hospital he was considerably exhausted, from pro- 
longed excitement, loss of sleep, etc. After a few days 
he became again very much agitated, and continued 
so, at intervals, for a period of three months. His 
agitation was more violent than that of his brother, 
but was similar in character. He ultimately became 
calm—in fact, for a time, was depressed, but later 
a more regular mental state was established; he 
became brighter than his brother, but never displayed 
much sane intelligence. His delusions became sys- 
tematized and marked his case as one of degenerative 
paranoia. His physical health improved and he was 
finally removed, by the county authorities, from the 
hospital to the County Institution, from which he soon 
after eloped and then emigrated to a neighboring State. 
The brothers resembled each other closely : I. M. was 
heavier and stronger than A. M., but their mental caliber, 
habits, and customs, as well as occupations, were similar. 
I. M. was a tinker, A. M. a peddler; they travelled 
together, lived a hermit like existence together, and were 
very devoted to each other. They were Jews, and in 
their religious observances were always together. These 
cases support what Ball1 has said regarding insanity 
in twins, viz., “ that they show the closest physical and 
1 B. Ball: Insanity in Twins. Tuke’s Dictionary of Psychologi- 
cal Medicine. 3 
moral resemblance; features, intellectual and moral dis- 
position coincide. ” Their mental aberration is developed 
simultaneously and the attacks are similar in character. 
In these cases both are pronounced paranoiacs. Further, 
the dominating influence of heredity is shown in these 
cases in the highest manifestations of its force. For 
these twins are brothers with a closer tie than that of 
other children in the same family, “ because they were 
born at the same time, conceived under identical cir- 
cumstances, they experienced the same influences during 
the whole period of gestation, and as in some, if not in 
all, cases there has resulted a striking resemblance of 
cerebral organization and of physical health.” Such 
can be the only possible origin of these pathologic symp- 
toms which, breaking out at the same moment, follow an 
absolutely identical course, characterized by the same 
phases and same observations.