CHAPTER VIII

THE ETIOLOGY OF MENTAL DISEASES

In reviewing the history of medicine there is nothing more discouraging than the references found in literature to the views entertained from time to time relative to the cause of mental diseases. To a certain extent this may be looked upon as an index of the progress of civilization. It must be admitted that it is at the same time, nevertheless, a reflection upon the medical profession which has never shown the interest in psychiatry that the importance of the subject warrants. It has been suggested that mental diseases did not play a prominent part in ancient history, owing to the fact that the law of the survival of the fittest automatically eliminated the insane and defective. As Tuke[56] says, "They perished in the course of nature, or were stamped out of existence; many of the perverse and morally insane were stoned to death; war destroyed a large number of feeble persons; while the Romans deliberately, and in the interests of the race, threw down from the Tarpeian Rock the children who were unfit to live." The papyri of the fifteenth century before Christ show clearly that the doctrine of demoniacal possession was generally entertained at that time.

One of the earliest attempts to explain the origin of mental diseases perhaps was that of Plato. "There are two kinds of madness, one arising from human diseases, the other from an inspired deviation from established custom." Hippocrates[56] had some very clearly defined views on this subject: "As long as the brain is at rest a man enjoys his reason; but the depravement of the brain arises from phlegm and bile, either of which you may recognise in this manner: Those who are mad from phlegm are quiet, and do not cry out or make a noise, but those from bile are vociferous, malignant, and will not be quiet, but are always doing something improper. If the madness be constant, these are the causes thereof; but if terrors and fears assail, they are connected with derangement of the brain, and derangement is owing to its being heated. And it is heated by bile when it is determined to the brain along the blood-vessels running from the trunk, and fear is present until it return again to the veins and trunk, when it ceases. He is grieved and troubled when the brain is unreasonably cooled and contracted beyond its wont. It suffers this from phlegm, and from the same affection the patient becomes oblivious." An interesting theory which he evolved was that the appearance of varicose veins or hemorrhoids tended to relieve the patient's mental suffering. Celsus subscribed to the black bile doctrine. Galen's teaching was that fatuity was due to moisture, while dryness produced sagacity. In cases where the whole body contained melancholy blood he recommended venesection. Thick and black wine was to be avoided, "as from it the melancholy humour is made."[57] This he described as a condition of the blood "thickened, and more like black bile, which exhaling to the brain, causes melancholy symptoms to affect the mind." The Roman custom of appealing to the household gods, sons of the Goddess of Madness, was quite significant. Horace, in speaking of Orestes, says: "Was he not driven into frenzy by those wicked Furies, before he pierced his mother's throat with the reeking point of his sword? Nay, from the time that Orestes passed for being unsound of mind he did nothing in any way to be condemned; he never dared wound with his sword either his friend Pylades or his sister Electra; he merely abused both, calling one a Fury, the other some other name suggested by his active or bright bile." In the story of Argive, Horace says that "his relations cured him with much labour and care, by expelling the disease and the bile by doses of pure hellebore."

Little progress was made, if any, by the time of the Christian era. In fact, as Clouston[58] says, "The mental pathology of the New Testament and of the early ages of Christianity was founded on the idea that the disease was a possession of the devil, and the feeling towards this afflicted class of human beings was naturally that of repulsion and hatred, their treatment following on those lines. Neglect, the whip, chains, confinement in stone cells, starvation, unsuitable medical treatment, speedy death were the natural results."

Passing to the seventeenth century we find that Sennert, a professor in Wittenberg, believed that maniacs evacuated stones, iron, living animals, etc., things not produced in the natural body and therefore caused by demons. He also believed firmly in witchcraft. Thomas Willis (1682) is said by some to have been one of the first to suggest a relation between insanity and pathological changes in the brain. Prochaska in 1784 went so far as to say, "We think, with Haller, that no light can be thrown upon it in any other way than by a careful dissection of the brains of fatuous persons, apoplectics, and such as have other disorders of the understanding." It would appear to have been the belief of Pinel that the primary seat of disease in mental conditions was in the stomach and intestinal tract. Spreading from these centers it caused a derangement of the mind when the brain became involved. The influence of the moon, as well as the stars, was spoken of by Hippocrates and admitted by Galen. To these ideas we owe the word lunacy which appeared in the laws of England in 1320 and may be found there today.

The influence of the moon on the mind was taken quite seriously. Rush seems to have been somewhat in doubt on this subject and suggested the probability of there being a kind of sixth sense involved—a perception of the state of the air, and of light and darkness, as Pritchard expressed it, to which we are insensible in health. It was thought that the full moon, by rarefying the air, increased the amount of light, thus affecting the mind. Dr. Rush noted that during an eclipse of the sun in 1806 "there was a sudden and total silence in all the cells of the hospital." He expressed the opinion in his "Medical Inquiries and Observations" in 1812 that there are few cases in which the insane feel the influence of the moon and that the excitement resulting in such cases is to be attributed to the resulting increase of light. It is interesting to note that von Feuchtersleben, an eminent German writer, in 1845 was unwilling to go on record as stating positively that the moon was not a factor in the causation of insanity. Esquirol, in his "Maladies Mentales," in 1838, branded this belief as a superstition, but admitted that there were certain facts which could not be overlooked. "It is true that the insane are more agitated at the full moon as they are also at the dawn of day; but is it not the bright light of the moon that excites them, as that of the day every morning? Nevertheless, an opinion which has existed for ages—which has spread over all lands, and which is consecrated by popular language—demands the most careful attention of observers." Dr. Allen of the York Lunatic Asylum was very firmly of the opinion that the moon had a decided influence on the time of death in mental diseases. This question was given very serious consideration by various writers as late as 1856.

In the meanwhile efforts were being made to ascertain the cause of mental disease by means of pathological researches. Morgagni,[59] one of the earlier investigators, came to the conclusion that the more common lesions were in the pineal gland, although he found some induration of the brain and various other well-defined changes. Arnold (1782) thought that insanity was due to an increased density of the cerebral substance, particularly, according to Tuke, "of those parts of the brain by means of which the soul is connected with the body." Pinel finally concluded that pathology had practically nothing to do with the problem and Esquirol in 1838 wrote very discouragingly on the subject. Early contributions of considerable importance were made, however, by Foville, Bayle, Greding, Calmeil, Guislain, Parchappe and others. These were confined almost entirely to a study of gross or macroscopic lesions of the brain. Griesinger in 1845 reviewed the pathological changes in the nervous system quite thoroughly as far as they were known at that time. It must be admitted that the greater part of our knowledge of the pathology of mental diseases was acquired at a much later date.

A very definite indication of the progress, or lack of progress, made in determining the etiology of the psychoses is the list of causes agreed upon at the International Congress of Alienists[60] in 1867:—1. Physical causes: Artificial deformities of cranium; convulsions of infancy and dentition; cerebral congestion (primary, not that which arises in the course of certain forms of insanity); organic affections of the brain; senility; pellagra; anemia; constitutional syphilis; intermittent fever; typhoid fever; acute rheumatism; gout and chronic rheumatism; organic affections of the heart; pulmonary phthisis; intestinal worms; other acute diseases; other chronic diseases; suppression of the hemorrhoidal flux; menstrual disorders; metastasis; alcoholic drinks; abuse of tobacco; other vegetable poisons; mineral poisons (lead, mercury, coffee, etc.); insolation; intense heat; intense cold; blows and falls upon the head; other traumatic causes. 2. Moral causes: Appertain to religion; education; love (love thwarted, jealousy); family affections; fluctuations of fortune; domestic troubles; pride; disappointed ambition; fright; irritation; anger; wounded modesty; political events; nostalgia; ennui; misanthropy; sudden joy; simple imprisonment; solitary confinement.

In 1897 the New York State Commission in Lunacy in its eighth annual report published an analysis of the assigned causes of insanity given in 39,369 cases admitted from 1888 to 1896. Of these 11,999 were reported as unascertained. In the remaining 27,370 cases the important "assigned causes" in the order of their frequency were as follows: Moral causes (including domestic trouble, loss of friends, business anxieties, pecuniary difficulties, grief, fright, disappointed affections, disappointed ambition, political excitement, religious excitement, etc.) 6,608, intemperance in drink 4,763, hereditary predisposition 2,095, old age 1,723, general ill health 1,681, epilepsy 1,605, ill health following overwork 1,092, masturbation 1,063, puerperal (including childbirth and abortion) 773, traumatic 608, climacteric 502, la grippe 442, sunstroke 402, physical diseases 375, syphilis 368, cerebral diseases 312, intemperance in drink and narcotics 277, congenital defects 223, shock from injury 167, fever 147, uterine and ovarian disease 132, pregnancy 109, privation and overwork 110, etc. These are given in detail not that they throw any light on the question of etiology but that they are quite significant as to the ideas prevalent on this subject only a few years ago. In justice to the Commission in Lunacy attention should be called to the fact that this tabulation does not purport to give actual causes but those officially "assigned" by the examining authorities or others interested. Clouston[61] in 1911, in making a statistical study of 11,346 cases admitted to the Royal Edinburgh Mental Hospital in the course of thirty-five years, enumerated a long list of causes shown in the hospital reports. It is interesting to note that they include nursing, disordered menstruation, self abuse, sexual excess, surgical operations, bronchitis, prostatic disease, lupus, commencing menstruation, transference of morbid action from other organs to the brain, excessive tobacco smoking, chloroform inhalation, excessive number of children, religious excitement, marriage, changes of residence, sedentary habits, political excitement, bad temper, the Queen's Jubilee, etc. As he says, "No other disease has anything like this list of 107 causes. A black and terrible roll it is. Poor humanity has much to contend with to keep sound in mind." Analyzing these statistical findings, Clouston concludes that "bad heredity, congenital defects, and previous attacks are the great predisposing causes, and that alcohol, the crises of life, epilepsy, the various forms of brain poisons and the gross brain and nervous diseases constitute the mass of exciting causes. Together they account for over seventy per cent of the defects and diseases of the mind that come under my observation."

A reference to the statistical reports of the past as published by the hospitals of this and other countries will show nothing radically different until within the last few years. It will readily be observed that fundamentals were almost entirely lost sight of and nonessentials overemphasized. Masturbation, for instance, is often a symptom of dementia praecox and other forms of mental disease, but is not now looked upon as an important etiological factor. The immediate cause, so-called, is usually a mere incident, often not without some significance, but bearing little if any definite relation to the fundamental underlying condition responsible for a mental breakdown. The studies of Meyer, Hoch, Kraepelin, Freud, Jung, Bleuler and many others have shown that in manic-depressive insanity, dementia praecox and various other psychoses we are dealing with very definite constitutional conditions, morbid temperaments, personality defects, etc., which are responsible for the maladjustments leading to the development of psychoses. Financial reverses, domestic difficulties, the death of near relatives, the ordinary hardships and disappointments of life, even ill health, do not as a rule mean the development of a psychosis in the normal, properly balanced individual. In the constitutionally predisposed, the love affair, the loss of a position, the upsetting factor, whatever it may be, is merely the "straw that breaks the camel's back" and is nothing more than an accident of fate, a pure coincidence. Any other comparatively trifling occurrence out of the ordinary, any difficult situation which the makeup of the individual could not adequately meet and react to, would have accomplished the same result. There are, however, of course, certain psychic traumas to which these inadequate personalities are particularly susceptible.

Experience has shown that without any doubt there are conditions for which defective heredity is largely responsible. It is often difficult to determine the actual rôle which this plays in a given case. Efforts have been made to reduce the study of these factors to a definite scientific basis. In 1865 Gregor Mendel,[62] Abbot of Brünn, published an account of a series of experiments made by him with the common pea (pisum sativum) which was destined to revolutionize our views on the subject of heredity. On crossing a tall with a dwarf plant, tall hybrids resulted with no intermediate forms. This inheritance is said to be due to the presence of a definite "determiner" in the germ plasm. All of his hybrids being of the tall variety, he designated that character as the "dominant," the dwarf being spoken of as the "recessive." On the fertilization of these hybrids he obtained another generation, which averages three tall plants to one dwarf. Further investigation showed that the dwarfs always bred true, as did about one out of three of the tall varieties, the remaining two behaving as did the original hybrids and giving three talls to one dwarf. He therefore observed that he was dealing with three varieties of inheritance, the dwarfs which bred true, the talls which bred true and the talls with a fixed proportion of talls and dwarfs. The phenomenon as noted by Mendel is not, however, universal in its application. Curiously enough no attention was given to Mendel's experiments until eighteen years after his death, when his work was rediscovered by de Vries, Correns and Tschermak in 1900.

Davenport[63] has shown that there are six possible matings of germ cells as illustrated by the pigment of the eye:—1. Both parents, pigmented iris (brown eyes) and duplex—all offspring with pigmented iris and duplex; 2. Both parents brown-eyed, one duplex, one simplex—all children brown-eyed, but half simplex; 3. One parent brown-eyed and duplex, the other blue-eyed—all children brown-eyed and simplex; 4. Both parents brown-eyed and simplex—one-fourth of the children brown-eyed and duplex, one-half brown-eyed and simplex, and one-fourth blue-eyed; 5. One parent brown-eyed and simplex, and the other blue-eyed—one-half the children brown-eyed and simplex, the other half blue-eyed; 6. Both parents blue-eyed—all children blue-eyed. It should be explained that a duplex origin means the inheritance of a character from both parents and simplex from only one. The principles of the Mendelian laws of heredity have been applied to a study of the color of the eyes and skin, the color and form of the hair, the stature, body weight and many other family traits such as musical knowledge, ability along artistic and literary lines, mechanical skill, etc. They have also been applied to the study of various diseases, such as Huntington's chorea, hereditary ataxia, deaf-mutism, feeblemindedness, epilepsy and insanity, etc.

Rosanoff[64] and Orr have suggested the following hypothesis relative to the transmission of the neuropathic constitution as based on the Mendelian theory:—1. Both parents being neuropathic, all children will be neuropathic; 2. One parent being normal but with the neuropathic taint from one grandparent, and the other parent being neuropathic, half the children will be normal but capable of transmitting the neuropathic constitution to their progeny, and half will themselves be neuropathic; 3. One parent being normal and of pure normal ancestry, and the other parent being neuropathic, all the children will be normal but capable of transmitting the neuropathic makeup to their progeny; 4. Both parents being normal, but each with the neuropathic taint from one grandparent, one-fourth of the children will be normal and not capable of transmitting the neuropathic makeup to their progeny, one-half will be normal but capable of transmitting the neuropathic makeup, and the remaining one-fourth will be neuropathic; 5. Both parents being normal, one of pure normal ancestry and the other with the neuropathic taint from one grandparent, all the children will be normal; half of them will be capable and half not capable of transmitting the neuropathic makeup to their progeny; 6. Both parents being normal and of pure normal ancestry, all the children will be normal and not capable of transmitting the neuropathic makeup to their progeny.

Just how much importance is to be attached to these theories is a difficult matter to determine. A study of a considerable number of families by Rosanoff[65] would appear to be very suggestive, although his conclusions must be looked upon as fairly conservative:—"On the whole, taking into consideration the limited amount of material as well as the various sources of possible error, the correspondence between the actual findings and theoretical expectation, as shown in the table, must be regarded as strikingly close." On the other hand, as White[66] says, "In dealing with the subject of heredity, however, it must not be forgotten that our ideas are of necessity largely founded upon hypotheses, as biological science has not yet unfolded a sufficient number of facts to make it possible to tell just how much, in any individual case, must be attributed to the inherent qualities of the "germ plasm" and just how much to the influences of environment. The view which is pretty generally admitted among biologists at present is that there is little warrant for the belief in the Lamarckian hypothesis of the inheritance of acquired characters."

The New York statistical tables on heredity were discontinued in 1907, at which time a total of 104,013 cases had been reported. In 31,290 of these no information was available, leaving a total of 72,622, excluding the not insane. A history of insanity was shown in the paternal branch of the family in 8.6 per cent of the ascertained cases, in the maternal branch in 10.1 per cent, in both paternal and maternal in 1.7 per cent, and in collateral branches in eleven per cent,—a total of 31.4 per cent in which some form of heredity was reported. These statistics relate only to insanity in the family history. There were so many sources of inaccuracy that it was not thought worth while to continue these studies after 1907. Comparisons between the heredity of mental cases and that of normal individuals have been rather surprising. Koller, for instance, as quoted by Kraepelin,[67] in a comparison of 370 healthy with a similar number of insane individuals found a history of psychopathic defects in the immediate families of fifty-nine per cent of the former and 76.8 per cent of the latter. Diem[68] in 1905 made an analysis of the family history of 1193 healthy individuals. This was compared with 1850 mental cases. Neuropathic heredity of some kind was found in 78.2 per cent of the mental cases and 66.9 per cent of the healthy individuals. There was, however, a history of mental diseases in the families of 38.3 per cent of the insane patients as compared with 7.1 per cent of the normal individuals. Somewhat different results were noted in a study of the parents. There was a paternal or maternal history of insanity in 18.1 per cent of the families of the mental cases as compared with 2.2 per cent in the cases of the normal individuals. In the direct parentage, Koller found mental diseases in 57.3 per cent of the families of the insane as compared with 28 per cent in the case of normal individuals. Kraepelin states that the influence of the father is greater in heredity than is that of the mother. The father, furthermore, usually transmits to the son while the mother influences the daughter more.

Heredity varies with the psychoses, having its greatest influence in the transmission of manic-depressive attacks, epileptic and hysterical conditions, nervousness, compulsive and impulsive insanity, sexual perversions and morbid personalities (Kraepelin). As the result of a study of two thousand cases, Pilcz[69] (1907) found that in alcoholism heredity was most likely to manifest itself in the form of alcoholism, epilepsy and imbecility or manic-depressive psychoses. In the progenitors of epileptics he found epilepsy and migraine. Apoplectics showed a family history of paralysis, arteriosclerosis, senile dementia or melancholia. Senile dementia preceded paralysis, arteriosclerosis, feeblemindedness and dementia praecox. Tabes and paralysis apparently frequently precede paralysis and dementia praecox. The various forms of alcoholic psychoses furthermore show a tendency to repeat themselves in the offspring of alcoholics. Similar heredity is said to be the general rule in manic-depressive psychoses, epilepsy and alcoholism, and to a less extent in arteriosclerosis. Heredity, in so far as it is related to mental diseases, may be said to be largely a question of the transmission of a neuropathic or psychopathic constitution or predisposition. Various psychoses are now held to be the direct result of constitutional causes or hereditary influences. This is probably true of manic-depressive insanity, Huntington's chorea, involution melancholia, dementia praecox, paranoia and paranoid conditions, epileptic psychoses, the psychoneuroses and neuroses, psychopathic personality and mental deficiency. It is true that some of these conditions develop as the immediate results of certain predisposing factors and that in frequent instances no evidences of heredity can be found. It is also true that various authorities maintain that a predisposition to the development of certain psychoses may be acquired. If, however, we assume that the above mentioned psychoses are constitutional in their nature and due primarily to heredity, it may be definitely stated that, based on recent statistical studies, hereditary influences account for from fifty-five to sixty per cent of the mental cases admitted to our institutions. It may be pointed out, as an objection to this suggestion, that although manic-depressive psychoses often develop in an emotionally unstable or cyclothymic personality and dementia praecox is associated with certain peculiarities of makeup, not all of these cases show clear evidences of constitutional origins. This is unquestionably true. It is equally true, on the other hand, that heredity is also probably very often a factor in the production of the senile and arteriosclerotic conditions, various nervous diseases, alcoholism and drug habits.

When we leave the subject of heredity we are on much more certain ground. There is no question whatever as to the rôle played by traumatism, senility, arteriosclerosis, syphilis, brain and nervous diseases, alcoholism, exogenous toxins, epilepsy, pellagra and somatic diseases in the causation of mental disorders. In an analysis of 4,079 cases examined at the Munich Clinic, Kraepelin[70] found the following factors involved:—1. Physical diseases, infections and gross brain lesions, 1.3 per cent; 2. Syphilis and metasyphilis, 10.3 per cent (general paresis 9.4 per cent); 3. Toxins—alcohol, morphine, cocaine, etc., 22.8 per cent (alcoholic psychoses 22.4 per cent); 4. Traumatic neuroses and prison psychoses, 2.5 per cent; 5. The presenile and senile psychoses, arteriosclerosis, etc., 5.6 per cent; 6. Dementia praecox, epilepsy, idiocy and imbecility, 27.2 per cent; 7. Psychopathic and hysterical states, and manic-depressive insanity, 30.3 per cent. Conditions existing in our hospitals and clinics are somewhat different. As the result of a study of over seventy thousand first admissions to forty-eight hospitals in sixteen different states we are now in a position to speak quite definitely as to the frequency of the conditions above referred to as etiological factors. Traumatic psychoses quite uniformly represent a little less than one-half of one per cent of the admissions to our institutions. The senile psychoses constitute approximately ten per cent and arteriosclerosis five per cent of the total. General paresis averages about twelve per cent in the New York hospitals and from seven to ten per cent in the other states. Cerebral syphilis amounts to a little less than one per cent of the cases. It should be said that in the large cities the rate for syphilis is, in some instances at least, twice as high as that given. Brain tumor, with all other brain and nervous diseases, only constitutes about one and one-half per cent of our admissions. Alcoholism, which has been responsible for as high as ten per cent of all admissions, from time to time, has been decreasing gradually during the last five years and in New York in 1920 constituted less than two per cent. Epileptic psychoses in our state hospitals amount to from one to two and one-half per cent of the total. As a general rule pellagra is not a factor of any consequence, amounting to less than one-half of one per cent of the admissions. In a few of the southern hospitals large numbers of pellagra are encountered. The psychoses accompanying somatic diseases are represented by from three to four per cent of the whole number. In addition to this, there is still a considerable number of cases reported from the hospitals as being caused by psychic trauma of various kinds. These represent the acute psychoses usually resulting from mental and emotional upsets but with nothing which definitely points to constitutional disorders or hereditary influences.

If we speak of predisposing causes, some reference should be made to the influence of the physiological landmarks which are of so much significance in the life of the individual in more ways than one—puberty, adolescence, the climacterium and the senium. A no less noteworthy factor in the female sex is the puerperium. These periods of life are of tremendous importance in the development of the psychoses. It is customary to speak of age, sex, race, civil condition, degree of education, climate, civilization, etc., as factors in the production of mental diseases. Not much is to be said on these questions, nor are they closely related to the subject. On January 1, 1920, there were 232,680 patients in the hospitals for mental diseases in the United States. Fifty-two per cent of these were men and forty-eight per cent women. This represents about the difference that has been shown for many years. The reduction in alcoholic psychoses may affect this ultimately. The striking exceptions to this ratio are Massachusetts and New York, where the number of women has slightly exceeded the men for a number of years. The admission rate for men is, however, slightly higher than that for women in both of those states. Less than one-half of one per cent of the patients admitted to the New York hospitals are under fifteen years of age. In that state approximately five per cent have been between fifteen and nineteen years old. In Massachusetts the percentage of persons admitted who were under twenty years of age has averaged 8.5 quite consistently for some time. The admission rate, for twenty to twenty-five, twenty-five to thirty, thirty to thirty-five and thirty-five to forty years of age in Massachusetts and New York has averaged from ten to eleven per cent for each of those periods for several years. From the age of forty to fifty the admission rate is about 8.5 per cent, and from fifty to sixty between five and six per cent. Nine per cent of the admissions in Massachusetts and eight per cent in New York are seventy years of age or over. The statistics on race, birthplace and the psychoses of the various races are shown in detail in the chapter on Immigration. The admission rate in New York is almost exactly the same for the married and the unmarried, the former constituting about thirty-nine per cent and the latter forty. In Massachusetts the single first admissions amount to about forty-three per cent and the married approximately forty per cent. Throughout the country generally the unmarried slightly predominate. The percentage of widowed in Massachusetts and New York varies from thirteen to fourteen per cent. The divorced constitute only about one per cent of all admissions. As to education, it may be said that about nine per cent of all first admissions are illiterate, from fifteen to twenty per cent can read and write only, about sixty per cent have had a high school and two per cent a college education. A study of economic conditions shows that from fifteen to seventeen per cent are dependent, from sixty to seventy per cent are rated as marginal, and from eleven to thirteen per cent as being in comfortable circumstances. In Massachusetts and New York about eighty-five per cent of the admissions come from a city environment and from twelve to fifteen per cent from rural communities. It is interesting to note that in 1919 eighteen per cent of the admissions in Massachusetts and New York were reported as being intemperate in their habits, with over fifty per cent abstinent.

In conclusion, it may be said that the important etiological factors in the production of mental disease are heredity, senility, syphilis, arteriosclerosis, somatic diseases, mental deficiency, epilepsy, diseases of the brain and nervous system, alcoholism, drugs, traumatism and mental stress and shocks of various kinds. It is hardly necessary to add that our information on this subject is far from complete.