Society Transactions

BOSTON SOCIETY OF PSYCHIATRY AND NEUROLOGY

Regular Meeting, April 17, 1924

C. M. CAMPBELL, M.D., President, in the Chair

INHERITANCE OF MENTAL DISEASES. DR. ABRAHAM MYERSON.

The term insanity as well as the term feeblemindedness and all terms which imply that there is necessarily a unitary character to psychiatry are more than useless they are pernicious in that they exercise an influence on the mind, which vitiates most of the work that has been done on the inheritance of mental diseases. There are independent groups of mental diseases which will be declared to have no hereditary value and others to run in families, as the phrase goes. That this "run in families" is necessarily hereditary, to be compared with mendelian heredity or the transmission of the major biologic qualities, seems to me not to be the case. The working hypothesis that wherever mental diseases appear to run in family groups some factor is at work which has been introduced from the environment and which has injured the germ plasm, is here advanced. This theory has been called blastophoria by August Forel, so that we may speak of this working hypothesis as the blastophoric concept.

There is no unity in feeblemindedness; the problem of the cretin belongs to the problem of endocrinology; the problem of the congenital syphilitic is the problem of syphilis; the problem of spastic diplegia and other spastic states, so often associated with idiocy, is a problem of trauma at birth, infectious disease, and the like. Occasionally it represents a failure in development, and there it is part of the problem of teratology and has no especial relationship to other types of feeblemindedness.

The conditions mentioned in the foregoing rarely have anything to do with heredity, or at least there is no obvious connection with defect or disease in an ancestor. They tend to be sporadic, to occur in families which cannot be differentiated from the ordinary groups in the community.

There also occur, especially among the more markedly defective, the idiots, cases in which nothing can be found that adequately explains the occurrence of the defect. As one studies the cases of marked defect, one is struck with the large number in which this represents a variation from the family level and without any hereditary background. I have as yet had no definite research experience with the higher grades of feeblemindedness, the moron type, which constitutes probably the largest group of the feebleminded. The data on which these are declared to be hereditary in origin, which appear in the textbooks and in the special writings of Goddard and Davenport, seem to me to be extremely faulty. Especially is there to be criticized as unscientific such family studies as "the Kallikaks" in which a field worker on the basis of hypothesis, guess, and intuition declares the dead and the quick feebleminded without the slightest definite reason for so doing. Making a diagnosis of moronity is a clinical matter attended with difficulties, but the field workers of Drs. Goddard

and Davenport have no difficulty in doing this on the basis of a court record, of a tradition, and of a cursory glance. That there are groups of the feebleminded in which the disease runs in families over one or more generations seems to be without doubt. How large a proportion this constitutes cannot be stated at present. It is unquestionably much smaller than has hitherto been assumed, and even in the cases in which it exists is not necessarily a fixed character persisting from generation to generation. It is interesting to note that the families founded by definitely known feebleminded persons discharged from Dr. W. E. Fernald's institution have not shown the inevitability of feeblemindedness in their descendants nor any trace of the much discussed prolificity which appears so conspicuously as a bogyman in the semiscientific and lay literature.

The Situation in the Psychoses.-There is no evidence to show that general paralysis depends on any hereditary factor. There is no evidence that the arteriosclerotic psychoses depend on anything but the appearance of arteriosclerosis in the brain, which seems to have the same background as arteriosclerosis in general. Cerebral arteriosclerosis occasionally occurs in members of the same family and an arteriosclerotic ancestor may have descendants with mental disease. These are mere coincidences, for it has been shown by Koller, Diem, Jolly and others that cerebral arteriosclerosis occurs more frequently in the ancestors and collaterals of the "sane" than the "insane." There is no scientific evidence that alcoholic mental disease is hereditary. Many of those who become alcoholic are peculiar, but the main basis of the alcoholic mental disease is alcohol operating in a curious manner on an individual. This idiosyncrasy to alcohol is a pharmacologic matter, to be compared to the reaction to bromids or morphin of certain persons. It has no distinct relation to psychopathy except that psychopathic persons often drink to excess. The study of Elderton, Pearson, and others is interesting in relation to this matter.

The foregoing three groups account for about 40 to 50 per cent. of all patients admitted to hospitals for the insane, and there is therefore at least that percentage in which no valid evidence has been brought forth to show the working of any force which can be compared to heredity. I come to a group of mental diseases which by all accounts and from all the literature appears in family groups-sometimes in several generations and sometimes in several members of the same generation.

Before taking up the situation in dementia praecox, manic-depressive psychosis and the involution diseases, a few statements in regard to certain data collected from the literature and especially from the work done by Mott in London and by myself in the Taunton State Hospital will be of interest. First, over 10 per cent. of the inmates of the state hospital at Taunton are related to one another closely. The largest groups of those related are the brother-sister group. The other groups in order are: sister-sister, brotherbrother, mother-daughter, mother-son, father-daughter, father-son, auntdescendant, uncle-descendant, cousin groups. Throughout the literature it appears that there are more females in the family groups with mental disease than males, and that so far as can be discovered by figures, the female transmits mental disease more frequently than the male. This, however, can be explained by certain facts conspicuous in the Taunton cases. The female insane have a much higher marriage rate than the male insane, especially in the dementia praecox group; the marriage rate of those with general paralysis and senile dementia is about equal to the normal marriage rate; the marriage rate of the male dementia praecox patient is extremely low, whereas the marriage

rate of the female dementia praecox patients is suprisingly higher than that of the male, yet distinctly less than that of the average female. Because the female in the group in which mental disease tends to occur marries more nearly in accordance with the normal marriage rate than does the male, she is more liable to have descendants and thus more liable to transmit mental disease. Again, the male of a family is much more apt to wander away from the district in which he was born than the female and thus to appear as a sporadic case in the statistics of some other institution. These facts are social rather than biologic in nature, and there is no conclusive evidence that the female is more liable to transmit mental disease than the male.

It also appears from the data gathered all over the world that the descendant (in family mental disease) is apt to have the mental disease at an earlier stage than does his ancestor and in a worse form. This phenomenon is called anticipation and has been greatly stressed by Mott and others. While it is true that there does appear to be some basis for the opinion that there is this tendency, it also appears that the way the statistics have been gathered explains part of the situation.

A survey of the world literature reveals only one case in which mental disease is actually known to have persisted for four generations, and that is in the case reported by myself. There are few cases compared to the total bulk of mental disease in which the mental disease occurs for three generations. Most of these also have been recorded among the Taunton cases. It appears probable that mental disease does not occur frequently for more than two generations. Oddities and peculiarities may persist, but difficulty in evaluating these or in tracing them makes it impossible to give them any great scientific value.

(a) If dementia praecox occurs in an ancestor and if his descendant has a mental disease, that mental disease is most likely to be dementia praecox. This opinion is based on a survey of the literature and of my personal studies. Occasionally, other mental diseases will occur in the descendant, but in so scattering an incidence as to be unimportant. It is quite noteworthy that there is a distinct tendency for the disease to manifest itself in a more serious form in the descendant and in greater liability to early dementia. (b) If manicdepressive psychosis occurs in an ancestor, the "insane" descendants seem to group themselves in two classes: the larger group which tends to be manicdepressive, and the smaller which tends to be dementia praecox. Most authors concur in this statement, although some state that dementia praecox is rare in such descendants. It may be stated that typical cases of manic-depressive insanity in an ancestor are followed by manic-depressive insanity in the descendant. The atypical cases, those in which there is some doubt as to the diagnosis, are followed by dementia praecox in the descendant. (c) Involution psychosis in an ancestor, if followed by mental disease in a descendant, is usually succeeded by dementia praecox. There is a surprising unanimity of experience and opinion on this point. (d) If there is paranoic mental disease in an ancestor and the descendant has mental disease, he is liable to have either paranoic mental disease or dementia praecox. It will thus be noted that in these cases there is some tendency for the psychoses to be dissimilar in clinical type and for the psychoses to trend toward dementia praecox in the descendant.

The Psychoses of Brothers and Sisters.-The psychoses of brothers and sisters tend to be alike. Dementia praecox in a group of siblings is apt to be uniform in its manifestations, although one classical case has been reported and personally observed in which there was a remarkable transition in type

from what appeared to be pure paranoia to hebephrenic dementia praecox in five sisters. Where manic-depressive insanity occurs in a sibling group, the manifestations are closely alike. It sometimes appears that one sibling becomes insane at the involution period while another becomes insane early in life. Nevertheless, although one will be called involution disease and the other perhaps dementia praecox, a close study will reveal the fact that the two psychoses are fundamentally alike. There are a few cases recorded in which manic-depressive psychosis and dementia praecox occur in the same sibling group. On studying them I have not been able to convince myself that typical cases of manic-depressive insanity and dementia praecox occur in the same sibling group. It is, however, stated by some authors that this is possible and does occur. If so, it is, relatively speaking, rare.

Normal and Abnormal Heredity.—Extensive studies made by Koller, Diem and Jolly indicate that certain characters are of no fundamental importance in determining psychopathic heredity. For example, it appears from the work of these three authors that neurasthenia and psychoneurosis, generally speaking, occur as frequently in the ancestry of the so-called normal person as in the ancestry of the abnormal person. It also appears that organic brain diseases are more common in the ancestry of the normal than in the ancestry of the abnormal person. This is especially true of cerebral arteriosclerosis, hemiplegia, apoplexy and the like, which are often given great weight in the literature. Certain types of alcoholism seem to occur somewhat more frequently in the ancestry of the abnormal than in the ancestry of the normal person, but not to a striking degree. Mental disease in an uncle or aunt appears as frequently in the history of the normal as in the history of the abnormal person. Mental disease in a father, mother, grandmother or grandfather occurs very much more frequently in the ancestry of the abnormal than in the ancestry of the normal person. Such diseases as cancer, tuberculosis, diabetes, and the like, seem to me to have no psychopathic bearing. Tuberculosis occurs frequently in the history of the ancestors of the feebleminded in institutions, but this is because tuberculosis is frequent in the social stratum from which these people come. At Dr. Fernald's institution in Waverly there is less tuberculosis than in the general community, largely because of the good hygiene of the institution. Therefore, much of what has passed as psychopathic heredity, nervousness, tuberculosis, diabetes, organic nervous disorders, and to a limited extent, alcoholism, has no psychopathic bearing. This is also true of much mental disease. The fact that an ancestor had had senile dementia or an arteriosclerotic psychosis has no bearing, so far as can be discovered, on the dementia praecox, feeblemindedness, or other psychotic manifestations in a descendant.

A Consideration of Certain Theories of Heredity.-Polymorphism, sponsored by Esquirol and Morel, and developed by Lombroso and a host of other writers, postulates that all forms of mental aberration from eccentricity of character to cretinism, including all of the psychoses, neuroses, epilepsy, and every departure from a hypothetical normal, are manifestations of the psychopathic constitution; that the disease condition manifests itself in a slight form in one generation and then increases degree by degree until, when a fourth generation is reached, the stage of idiocy appears and the stock then disappears. This remarkable theory which still shows its effects in all writings on the subject must be evaluated according to the time in which it originated. Not only may we say that information was lacking at the time when this formula for heredity was promulgated, but we may say also that the formula is never observed in operation. The only four-generation group that has been dis

covered is the group I have described in which no such transition occurs. On the whole, it may be stated that polymorphism in the main may be rejected, although there is some evidence of a limited type of transformation and a limited linking together of various mental states.

Of late years biologists have introduced the concept of mendelian heredity into psychiatry. Mendelianism in psychiatry can by no possibility be proved at the present stage of psychiatric knowledge. It is based on polymorphism. The Blastophoric Theory of Forel.-Forel states in opposition to what is usually considered true weismannism that the environment in the form of toxic substances, and especially alcohol, may so alter the germ plasm as to produce defective individuals, and that this defect may persist for generations. As a matter of fact, it may be stated that it has not been shown that alcohol, or syphilis for that matter, alters family groups in a permanent way or more than one generation of individuals. The effects of alcohol in an ancestor have not been studied in the case of man; but there is no reason at present to doubt that the environment may alter generations of individuals in a more or less permanent way. To corroborate this point of view the work of Stockard and his colleagues and of others may be cited to show that, irrespective of the problem whether or not acquired characteristics can be inherited, the environment may be so brought to bear on the individual as to alter his germ plasm, and this in a manner that persists for several generations. It is important to know that experimental science has substantiated the opinion that what happens to an ancestor may, and in certain instances does, alter the qualities of the descendant. This is not really opposed to weismannism.

If it comes to a choice between the present attitude taken by psychiatry toward mental diseases and an attitude which denied that there was any inheritance of mental diseases, I should favor as more true and more conducive to progress, the latter. The first view applies to a limited number of the types of the psychoses, and even in the case of these does not explain the origin of familial mental disease. The present view leads to pessimism and the adoption of a policy that does not aim either at investigation of causes or at therapeutics. Psychiatry needs to investigate the inheritance of mental diseases and needs to separate out the groups, to study each group from every angle, and to keep in mind that seventy-five years ago the leading medical men of the world were as firmly convinced of the inheritance of tuberculosis as psychiatrists today are of the inheritance of most mental disease.

DISCUSSION

PROF. G. H. PARKER: It is hazardous for a biologist to speak to a body of experts on a subject they know so well and that he knows so poorly, but we can all agree on methods of investigation. I know of nothing more depressing than to see a young person who has had three or four weeks' experience in some laboratory turned out on the community to learn the nervous composition of the people of the community. This is surely an unscientific method. There is only one kind of science in medicine, as in biology, and that is good science. We must keep away from all other kinds.

The whole question that has been raised by Dr. Myerson about inheritance gives you some idea of what the biologist is facing. The question is no more complicated in man than in mice or in guinea-pigs. The mendelians have attempted to divide their material on the basis of unit characters. This is quite artificial. Different eye colors may be taken to represent such characters, but eye characters are so abundant that they merge one into another and cannot be