=Many Types of Insanity.--=The commonest manifestations of insanity are undue depression, apathy, excitement, instability, obsessions, hallucinations and delusions. Some mental disorders are a.s.sociated with recognizable structural changes in the nervous system, but the structural basis of many is not known.
In general there is more doubt about the inheritability of some of the insanities than about cases of mental deficiency. The term insanity is merely a loose descriptive one, and we shall gain little definite knowledge about the inheritance of such maladies until we study each separate insane diathesis specifically. Psychiatrists recognize many different forms of insanity, some of them very distinct from others and the product of unrelated underlying causes. Often it is only a question of degree or sometimes a matter of chance as to whether a given individual is certified as insane or not. A neuropathic person who manifests certain anti-social activities is sure to be cla.s.sed as insane, whereas another individual with the same diathesis in a less degree might pa.s.s unrecognized. It is almost impossible in some instances to tell just where the border-line between a neuropathic and a normal const.i.tution lies. Many of the idiosyncrasies of the insane, indeed, are merely exaggerations of characteristics seen in normal people. Recent studies of the psychology of the insane show that most of their hallucinations and delusions are closely related to some previous mental experience they had before becoming insane. And it has been found that the surest means toward removing the obsessions of the patient in curable cases is to ferret out these earlier experiences and correct the wrong impressions regarding them. Again, certain forms of insanity do not become manifest except as special reactions to particular environmental conditions, and if these conditions do not happen to occur, then the neuropathic const.i.tution though existing would not be revealed. Certain critical periods of life such as p.u.b.erty, pregnancy and the close of s.e.xual life are particularly likely to test out the mentally unstable, although such individuals may have maintained normal mental balance up to the crisis in question.
=Not All Insanities of the Same Eugenical Significance.--=Of the various kinds of insanity some seem to be of much greater eugenical significance than others, not only because they are strongly heritable, but also because of the periodicity of the attacks. The patient may be repeatedly in and out of the asylum and in his sane intervals wholly unrestrained as far as propagating his kind is concerned. _Manic depressive_ psychoses and _dementia prec.o.x_ in the order named represented the largest number of admissions to the Wisconsin State Hospital for the Insane in 1911 and 1912, and both of these very frequently have a hereditary basis. Fig. 36, a chart showing the insanity in a local family as worked out by one of my pupils, is a good example of a recurrent type. The father (Fig. 36, p.
241) was about eighty-two years old when the record was made. His memory was poor and he could not talk connectedly, although this was possibly attributable to old age rather than to insanity. His brother, written to in Ireland, stated that to his knowledge there had never been insanity in his side of the family. The mother (2) was insane at nine, again at twenty-nine and again at thirty-six. In her later life she has been in the Mendota Hospital for the Insane five times and in the County Asylum twice.
The eldest daughter (3) has been in the State Asylum five times and is now at home. The next daughter (4) spent five months in the asylum in 1885.
Another daughter (5) likewise spent a short period in the asylum. Two sons (6, 7) have each spent two periods in the asylum, and a third son (8) has had an attack of insanity. The youngest child died at the age of three.
Thus of the eight adult children six have been insane at some time. The cases in this family seem all to be instances of manic-depressive insanity.
[Ill.u.s.tration: FIG. 36
Inheritance of insanity in the L---- family. See text for description.]
=A Neuropathic Const.i.tution May Express Itself Differently Under Different Conditions.--=Some of the difficulties of getting genealogies of specific forms of insanity are obvious from the following quotations chosen from the works of eminent psychiatrists. Kraepelin, for instance, expresses the opinion that: "The psychopathic charge of a family may reveal itself not only by the appearance of mental disorders but also by other forms of manifestation. Here belong before all, those diverse slighter deviations from mental health which go to make up the borderland of insanity: nervousness, states of anxiety and compulsion, const.i.tutional depressions, slight hysterical disorders and forms of feeble-mindedness, tics; also odd characters, peculiarities in mode of living, criminal tendencies, lack of self-control, intemperance, love of adventure, mendacity, suicide on an inner basis."
From the volume of Church and Peterson on _Nervous and Mental Diseases_ a further confirmatory opinion may be cited: "In determining the factor of heredity we must not be content with ascertaining the existence of psychoses in the ascendants, but must seek, by careful interrogation of various members of the family, for some of the hereditary equivalents, such as epilepsy, ch.o.r.ea, hysteria, neurasthenia, somnambulism, migraine, organic diseases of the central nervous system, criminal tendencies, eccentricities of character, drunkenness, etc., for these equivalents are interchangeable from one generation to another, and are simply evidence of instability of the nervous system. It is the unstable nervous organization that is inherited, not a particular neurosis or psychosis, and it must be our aim in the investigation of the progenitors to discover the evidence of this."
=Certain Forms of Insanity, But Not All, Seem to Behave as Mendelian Recessives.--=A number of psychiatrists and investigators of the inheritance of insanities (Rudin, Lunborg, Davenport, Rosanoff, Jolly), although working independently and in different countries, concur in the opinion that manic-depressive insanity, dementia prec.o.x and allied psychopathic conditions tend to occur after the manner of a Mendelian recessive. On the other hand such maladies as Huntington"s ch.o.r.ea are transmitted as a dominant and in all probability at least half of the children of an afflicted individual will inherit and manifest the defect.
As to inheritance of various other psychoses we have too few accurately charted pedigrees for most types to make very positive statements about their degree or manner of inheritance. Little can be said beyond the statement that there is a decided tendency for various forms to recur in offspring. Where more than one case of insanity occurs in a given family or stock it is strong presumptive evidence that a hereditary defect is at the bottom of it. As Doctor Wilmarth says, "Mental accident may occur in any family, but it is rarely a second case occurs unless there is a tendency to nerve degeneracy." For example, of 818 insane at the Wisconsin State Hospital for the Insane during the biennium 1909-10, 187, or practically one-fourth were positively known to have insane relatives. Of these, 24 had insane fathers, 31 insane mothers, 30 insane brothers, 23 insane sisters, 25 insane uncles, 21 insane aunts, and 21 insane cousins.
Where definite information could be obtained it was found that of the 5,700 admissions of insane patients to the New York state hospitals during the year ending September 30, 1911, 27.7 per cent. of the cases showed a history of insanity in the family and an additional 22.9 per cent. showed a history of alcoholism, nervous diseases and the like.
=Grades of Feeble-Mindedness.--=As to the various grades of feeble-mindedness, while no sharp lines of demarcation can be drawn, a rough and ready test usually applied is the relative ability of such subnormal individuals to take care of themselves. In all, the conditions exist from birth or shortly after. _Idiots_ are such defective individuals as are unable to take care of themselves even to the matter of guarding against common physical dangers. Their mentality does not progress beyond that of a two-year-old child. _Imbeciles_ can take care of themselves in the cruder physical ways, but are unable to earn their living. Their mental age ranges from three to seven years inclusive. _Morons_, or the "feeble-minded" in a more specific usage of the term, can under proper direction become more or less self-supporting but they are as a rule incapable of undertaking affairs which demand judgment or involve unrestricted compet.i.tion with normal individuals. Their intelligence ranges with that of normal children from seven to twelve years of age. The last cla.s.s grades up insensibly into the shiftless, ne"er-do-well types which exist in every community. It is the hordes of the feeble-minded in the restricted sense that afford our most serious problems to-day. The idiot and the imbecile are usually early and easily recognized and are kept more or less under restraint, but the higher grades of feeble-minded, the so-called moron type, can be detected often only by carefully devised tests.
=About Two-Thirds of the Feeble-Minded Have Inherited Their Condition.--=Concerning the various types of feeble-mindedness there is strong evidence that heredity is a factor of greater magnitude than in most insanities. All facts point to the conclusion that most mental deficiency is strongly inheritable and that the majority of our defectives of this type come from degenerate stocks. Practically all specialists at the heads of asylums and homes for the mentally deficient concur in the opinion that about two-thirds of the cases are hereditary. For example, Doctor Alfred Wilmarth, superintendent of the Wisconsin Home for Feeble-minded, says: "My own observations, and those of others in this country and Europe, would indicate that at least two-thirds of the feeble-minded have defective relatives."
In his study of two thousand children tested by the Binet measuring scale for intelligence, Doctor Henry H. G.o.ddard, director of the Department of Research at the Training School for Feeble-minded at Vineland, N. J., remarks concerning heredity of feeble-mindedness: "But we now know that sixty-five per cent. of these children have inherited the condition, and that if they grow up and marry they will transmit the same condition to their offspring. Indeed, we know that this cla.s.s of people is increasing at an enormous rate in every community and unless we do something to stop this great stream of bad protoplasm we shall some day be swamped in a sea of degeneracy."
E. R. Johnstone, superintendent of the training school at Vineland, N.
J., in a recent bulletin remarks concerning feeble-minded and epileptics, "We are now convinced that from sixty to eighty per cent. of the cases are hereditary."
Again, we find Doctor A. C. Rogers, superintendent of a school for feeble-minded in Minnesota, saying, "We have no survey of mentality in this country except in very small areas, but probably about sixty-five per cent. of the feeble-minded children that we know of are feeble-minded from heredity; that is, they come from families in which there is much feeble-mindedness, usually a.s.sociated with various neuroses or psychosis.
There are about thirty-five per cent. approximately that are acquired cases. These cases develop from various things. Full development may be prevented during gestation, or early childhood, or early adolescence, but these acquired cases are entirely distinct from the hereditary ones."
In a recent paper Doctor Martin W. Barr, chief physician for the Pennsylvania Training School for Feeble-minded Children, says: "In my individual study of 4,050 cases of imbecility, I find 2,651, or 65.34 per cent., caused by malign heredities; and of these 1,030, or 25.43 per cent., are due to direct inheritance of idiocy; and 280, or 6.91 per cent., to insanity." From these figures it will be seen that Doctors Barr, G.o.ddard, Wilmarth, Johnstone and Rogers all agree in their estimates; namely, that two-thirds of our imbeciles are so through inheritance.
=Some Results of Non-Restraint of the Feeble-minded.--=The following excerpt from a paper by Doctor Barr, is a fair sample of what happens when such defective individuals are not restrained from propagating their kind:
"My own study and observation alone, of over 4,000 degenerates, shows such examples as: A man 38 years of age, the father of 19 defective children, all living, he and his wife both under par mentally; as was another couple, with 9 imbecile children; an idiot woman with 7 idiot children. A forcible instance is that of a man with two daughters and one illegitimate grandchild, all feeble-minded.... I could name a family, one of the proudest in the land, where there are five children, an aunt and two uncles, all feeble-minded.
"Yet another, which in seven generations numbering some 138 individuals, records 10 still-born children (premature births), 16 insane, 7 imbeciles, 3 epileptics and 32 with mental peculiarities so p.r.o.nounced as to occasion remark. Of the 138 there remain 80 apparently normal, who are nevertheless hopeless slaves of a neurotic heredity, direct or collateral.
"In a study of 15 imbecile girls, 3 were recognized prost.i.tutes, 9 had each 1 illegitimate child (2 being the result of incestuous intercourse with brothers); 1 had 2; 2 epileptics had, the one 3, and the other 4 idiot children.
"Four feeble-minded women had 40 illegitimate children.
"A feeble-minded woman living in an almshouse since early childhood, allowed to go out to service periodically, had given birth to six illegitimate children, all inheriting her defect.
"An imbecile drunkard is the father of three feeble-minded children.
The daughter, seduced before the age of sixteen, gave birth to an idiot child; one son is a harmless imbecile, but the other is a moral imbecile, a s.e.xual pervert, a thief on the streets, and a pyromaniac, firing in sheer wantonness a large mill property.
"Another shows the entire family for three generations below normal.
Father, mother, mother"s sister, and father"s uncle, all imbecile.
Five children feeble-minded. One girl had a proposal of marriage, and one boy is married to a feeble-minded girl.
"One insane woman, whose brother and sister committed suicide, had five sons. The oldest, feeble-minded, a drunkard and hobo, had one son, a criminal. The second son, insane, had three imbecile children.
The third, an insane epileptic, had three imbecile sons, one of whom was an epileptic. The fourth son was insane. The fifth, apparently normal, had a morally imbecile son and an epileptic daughter."
Yet striking as is the inheritance of these maladies, Doctor Barr points out that of the 10,000 known cases of feeble-mindedness in Pennsylvania, only 3,500 are sequestrated. This leaves a balance in that state of 6,500 totally irresponsible individuals to work havoc in society by producing their kind.
=Inheritance Not a Factor in Some Cases of Mental Deficiency.--=On the other hand as our data show, there remain about one-third of the mentally deficient type to be accounted for on other than a basis of heredity. As already noted, some of these are doubtless the product of suppressions of normal development by various extraneous factors operating before or shortly after birth. There is one cla.s.s particularly, estimated by some authorities as const.i.tuting as high as thirty per cent. of the feeble-minded which is unusually puzzling. These are the so-called mongolians. The name is given because the features of such individuals bear more or less resemblance to those of some of the Mongolian races. The defect does not seem to be hereditary although it is usually congenital.
It appears to be due to something which interferes with prenatal development. Whatever the conditions, whether lack of nutrition in the mother, alcoholic or other poisoning, the cases seem to be as hopelessly incurable as are the hereditary forms. From the social standpoint, of course, such individuals are in their immediate generation, as incompetent or as dangerous to society as those suffering from the more surely known hereditary forms of mental defect.
=Epileptics.--=Although epileptics are not cla.s.sed as imbeciles ordinarily, as a matter of fact no sharp distinction can be drawn between the two cla.s.ses. Doctor Wilmarth says, "Epilepsy and mental deficiency are as closely related as branches on the same tree.... Over one-half and perhaps two-thirds of all feeble-minded are subject to convulsive seizures at some period of their lives, and we are never surprised at the appearance of epilepsy in any feeble-minded person. On the other hand, so small a percentage of epileptics maintain normal mental actions as hardly to be worth consideration ... even those who retain a normal mind in the early stages of the diseases almost infallibly become imperfect later."
How slight a chance the epileptic has of ever becoming normal may be inferred from a statement made by Doctor Frank Billings in a paper read before the Illinois State Medical Society in 1909 to the effect that "ten per cent. or more can be cured by proper care."
According to the estimates of "The Committee of Fifty" in the state of Illinois, who have been agitating for the establishment of a colony for epileptics, there are 10,000 of these unfortunates in that state. The consensus of opinion of experienced workers in various states is that there is about one epileptic to each three hundred fifty to five hundred inhabitants.
=In Heredity Conditions of Feeble-Mindedness Are Probably Recessive to Normal Condition.--=As to the mode of inheritance of the various forms of feeble-mindedness, the evidence points to such defects in the main as being recessive. However, no particular grade can be picked out and shown to be a pure recessive. For instance, the children of two epileptics will be defective but it is impossible to predict always whether the defect will appear as epilepsy or feeble-mindedness. This is doubtless due to the fact that mental deficiencies even of the inheritable type are not all due to the same specific cause, and in many cases the individual is defective in more than one direction. If one or more of a great number of units which are necessary for complete mental development are lacking, obviously mental deficiency will result. In other words, feeble-mindedness and allied disorders may not be definite characters, but simply evidences of the fact that the nervous system has not developed all factors necessary for normal mental coordination. G.o.ddard, however, one of our best authorities on the heredity of feeble-mindedness, is inclined to regard the condition as a unit character, "due either to the presence of something which acts as an inhibitor, or due to the absence of some stimulus which sends the normal brain on to further development."
Supposing nervous defects finding expression in feeble-mindedness, epilepsy and related conditions, to act as a Mendelian recessive, then the marriage of one such defective with another should yield only mentally enfeebled offspring. How nearly this expectation may be realized is seen from the following examples.
In an extensive study[9] of feeble-mindedness, just from the press, Doctor Henry H. G.o.ddard points out that of 482 children with both parents feeble-minded all but six were feeble-minded. Even the exceptions may be apparent rather than real as there is possibility of mistake in judging the condition of the parents or of the children themselves. Moreover, with the feeble-minded one is not always sure of the paternity of a child, as is instanced by Doctor G.o.ddard in a case quoted from Doctor Emerick in which of twelve children in a white family with both father and mother feeble-minded ten were feeble-minded and two were not, but these two were _mulatto_ children.
In a paper by Weeks (_The Inheritance of Epilepsy_), in part an extension of an earlier joint paper by Davenport and Weeks, is recorded among others a study of twenty-seven fraternities in which both parents were either epileptic or feeble-minded. Of the 28 progeny, 19 lived long enough to reveal their mental state. Of these 3 were feeble-minded, 8 epileptic and 8, from parents who developed epilepsy late in life, were what Doctor Weeks terms "tainted." In 15 fraternities in which one parent was epileptic and the other feeble-minded he found there had been 81 conceptions. Of these 7 were too young to cla.s.sify and 19 had died before fourteen years of age. Of the remaining 55, 28 were epileptic, 26 feeble-minded, and 1 insane. Again, in 9 families in which the parents were both feeble-minded, of the 38 surviving offspring who were old enough to cla.s.sify, 7 were epileptic, 29 feeble-minded, and 2 drunkards. In 5 families where one parent was insane and the other epileptic or feeble-minded, 5 children died before the age of fourteen, the condition of 2 was unknown, 2 were epileptic, 4 feeble-minded, 1 insane, 8 tainted, and 7 seemingly normal. Regarding the latter Doctor Weeks says they came from two families where in one case the father"s insanity seemed to be traumatic and in the other alcoholic.
In a few cases where the defect in one parent has apparently been of a type different from the defect of the other parent a "normal" child was produced. That is, presumably each parent carried normality in the trait defective in the other so that the child became simplex with reference to each defect. Davenport points out that not infrequently two deaf-mutes whose defects are due to different causes may have normal children.
In general, however, the reasonable expectation is that where two feeble-minded individuals marry, a very common occurrence, the children will all show mental deficiency. A mating between a feeble-minded person and one of perfectly normal stock will apparently result in normal children although they will be carriers. There is some evidence, however, that such carriers may occasionally show "taints" of abnormality in the form of migraine (nervous sick headache), alcoholism, queerness, violent temper, etc. Thus according to the studies of Doctor Weeks, "In 50 matings where at least one parent is migrainous, there were 350 conceptions, of which number enough is known of 212 to cla.s.sify 55, or 26 per cent., as epileptic; 12, or 6 per cent., as feeble-minded, with the others tainted or normal. In the 131 matings where at least one parent is alcoholic, there were 845 conceptions. Of the 494 cla.s.sified, 151, or 31 per cent., were epileptic; 54, or 11 per cent., feeble-minded, with the balance tainted or normal." Marriage between two carriers will cause the defect to reappear in active form in approximately 25 per cent. of the offspring and 50 per cent. will continue to be carriers.
=Many Apparently Normal People Really Carriers of Neuropathic Defects.--=There is considerable evidence that many apparently normal individuals of our average population are in reality carriers of some form of neuropathic defect, some authorities placing the proportion provisionally at over thirty per cent. This being true, then it is easy to explain the apparently unaccountable appearance of epilepsy, feeble-mindedness, or similar defects among the children of what pa.s.s for normal stocks. The probabilities are that in many cases it means simply that the parents of the defective children have been carriers.
As to the contention that in preventing the propagation of the feeble-minded we may be depriving the world of geniuses, Doctor G.o.ddard remarks: "It is a significant fact that in our three hundred family histories totaling 11,389 individuals not a single genius has been found.
Not only are there no geniuses but the fact can not be too strongly emphasized that even the people who are considered normal ... are not as a rule people of average intelligence...." However, between insanity and genius he finds more kindred spirit.
=Tests for Mental Deficiency.--=As to tests for mental deficiency, the one commonly meted out to victims in the every-day world is the social-economic one of survival in the compet.i.tions of life. The mentally deficient fail. Although often unrecognized as feeble-minded they drift through life social and economical derelicts who have to be supported by the community.
Of laboratory tests many have been devised. While all yet leave much to be desired, still through their application the majority of mental defectives can be detected. Fairly accurate standards of normality have been established from which the relative degree of "backwardness" can be determined. We have just awakened to the importance of detecting defectives early in life, hence many of our tests have been planned with reference to children. They are based not so much on training or conscious learning as on fundamental processes which develop at certain ages in children. Another impetus toward securing adequate criteria of mental deficiency has been the crying need of having some easily applied standard for detecting the very large numbers of defective immigrants who are continually seeking to enter the United States.
Most of the methods consist of "performance" tests which are planned to test the powers of perception, concentration, application, ingenuity and education of the subject. Previous environment, education and the difficulties under which the subject may be laboring at the time of the test must, of course, be taken into account. It is particularly difficult to get adequate tests for the immigrant which will enable one to distinguish between ignorance, stupidity, fear and temporary psychic depression on the one hand, and congenital mental deficiency on the other.
Perhaps the most successful single set of tests for mental deficiency is that known as the Binet-Simon Scale. From an examination of large numbers of French school children Binet constructed a scale of tests of increasing complexity accurately graded to age and previous training of the average normal child. In the Binet-Simon system tests are given for each age from three years to thirteen. When a child successfully pa.s.ses the tests for his age he is cla.s.sed as normal. If he succeeds only in tests which normally are those given for a child a year younger then he is backward to the extent of one year. Similarly he may show by these graded tests that he is backward to the extent of two years, three years and so on. If a child is more than three years backward according to the test he is regarded as mentally defective. Various corrections and adjustments of the original scale have been worked out to allow for unevenness in mental development. On the whole the scheme works out satisfactorily when applied by one skilled in its use. The att.i.tude of the examiner, however, is of so great importance that the tests are of less value in the hand of inexperienced workers. A revision of the scale to adapt it better to American children has recently been made by Doctor G.o.ddard.[10] Besides the Binet-Simon tests various performance tests, standardized for children of different ages, such as Seguin"s form board, Healy"s pictorial completion test, Fernald"s construction puzzle, the Rossolimo test, De Sanctis test, etc., are used by different investigators. Questions designed to reveal moral tone are also employed. Doctor Howard A. Knox, a.s.sistant surgeon United States Public Health Service, in a recent article[11] gives an interesting account of the tests applied to determine the exact mentality of immigrants entering the United States together with a brief review of various tests. A full account and discussion of the various tests for the mentally subnormal will be found in a recent publication by Doctor William Healy,[12] director of the Juvenile Psychopathic Inst.i.tute, Chicago.
=The Backward Child in School.--=It is only in recent times that we have come to realize the seriousness of the problem which the backward child presents in our schools. It is of the utmost importance to discover early in school life which of the backward children owe their condition to adenoids, defective sight or hearing, poor nutrition, imperfect circulation, or other remediable defects, and which are the victims of innate mental deficiency. The treatment of the individual must be very different in the two cases. In the one the condition can be cured by proper manipulations or other treatments; in the other it can only be ameliorated. All school children who are two or three years below grade should be rigidly inspected by the medical examiner.
From a study of about two thousand children comprising the first five grades of an entire public school system G.o.ddard found that eighteen per cent. were definitely "backward." Of these between two and three per cent.
were actually feeble-minded, the condition in the remaining fifteen per cent. being presumably capable of correction. Other similar surveys have given practically the same results.