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.
CHAPTER IX
IMMIGRATION AND MENTAL DISEASES
A history of the development of our western civilization is very largely a study of the process of assimilation of the various racial elements representing a new population. While it must be conceded that we are indebted to European countries for much that has been contributory to the welfare and success of American institutions, it is equally true that the tremendous increase in mental diseases and defects here is to be attributed in no small degree to immigration. This constitutes a problem of social and economic importance which is worthy of serious consideration. Perhaps no better evidence of this fact can be offered than a study of such statistics as are available relating to the thirty-three millions of people coming to the United States from other countries during the last century. This would seem to be particularly indicated at this time, in view of the fact that the conclusion of the war has brought about the necessity of a new adjustment of our relations with other countries.
Immigration to the United States has varied greatly from time to time. It is a well known fact that the founders of our government were practically all of English, Dutch, German or Scotch-Irish extraction. Unfortunately no information of any consequence is available regarding the aliens entering the country prior to 1820, when their study was first undertaken by the federal authorities. As far as can be determined, during the ensuing ten years about 128,000 were admitted at the various ports of entry. The history of immigration since that time has been determined very largely by existing conditions in other countries. The famines and political disturbances in Ireland between 1840 and 1850 were the occasion of a large influx, concededly of a highly desirable type. The nature of the tide of incoming immigrants was changed by the revolutionary troubles in Germany during the decade following 1848. There was a decrease for a time during the civil war. This was soon followed by a considerable increase which continued quite consistently until the outbreak of the world war. There would at this time seem to be every reason for thinking that an unprecedented invasion can be expected during the next twenty-five years as a result of conditions prevailing abroad unless some restrictions are imposed. In 1850 and 1860 the number of Irish people in the United States exceeded the German born. The 1890 census showed a predominance of the latter race and they have exceeded the Irish element in the population for some time. Nearly a million Germans were admitted between 1880 and 1885. Since 1890, however, the number of Irish and Germans entering have both decreased markedly. After the Spanish-American war a great increase in immigration was noted and the rate of admission per year reached a million in 1905, but the source of supply had entirely changed.
Salmon[71] has shown that in spite of the fact that in 1882 only 12.9 per cent of all incoming aliens admitted were from those countries, eighty-one per cent of all immigration from Europe in 1907 came from Austria-Hungary, Bulgaria, Greece, Italy, Montenegro, Poland, Portugal, Roumania, Russia, Servia, Syria and Turkey. In 1882, 87.1 per cent of those admitted came from England, Germany, Holland, Norway, Sweden, Switzerland and Belgium. The races represented by the new tide of immigration, according to Salmon, were Slavic, thirty per cent, Italian, twenty-six per cent, and Hebrew, fifteen per cent, the remainder being made up of various other miscellaneous elements. This change is shown by the fact that the immigration from Austria-Hungary, which amounted to only 711,926 from 1820 to 1896, increased to 2,303,323 during the first decade of the present century. Five hundred and thirty-four thousand three hundred and thirty-six were admitted from Russia between 1820 and 1896 and 1,756,027 between 1900 and 1911. The Italian immigration, which amounted to 676,826 between 1820 and 1896, increased to 2,228,759 between 1901 and 1911 (Salmon[72]). The numerical status of immigration by decades is shown in the following table: