The more important mental disorders which are supposed to develop on a hereditary basis are: arrests of development, epileptic psychoses, constitutional psychopathic states, dementia præcox, paranoia, manic-depressive psychoses, involutional melancholia, and allied conditions. Of 7664 cases admitted to the New York state hospitals during the year ending September 30, 1913, 3326, or 43.4 %, belonged to these groups.1

Alcoholism. The most trustworthy experimental data that are available, among which may be mentioned those of Schneider, Hellsten, Mayer, Aschaf

2

1 Twenty-fifth Annual Report of the State Hospital Commission, Albany, N. Y., 1914.

2 Pflueger's Archiv f. d. gesamte Physiologie, Vol. XCIII, p. 451. 3 Abstracted in Muenchener medicinische Wochenschrift, 1904, p. 1894.

4 M. Mayer. Ueber die Beeinflussung der Schrift durch den Alkohol. Kraepelin's Psychol. Arb., Vol. III, p. 535.

fenburg,1 Smith,2 Kürz and Kraepelin,3 seem to show that even moderate indulgence in alcohol, though producing in the subject a sense of well-being and of increased physical and mental ability, in reality causes impairment of muscular power and coördination and of mental efficiency.

Excessive indulgence produces the sufficiently familiar picture of drunkenness, and such excesses, if frequently repeated, are apt sooner or later to produce one or another of the alcoholic psychoses, of which the more important are: delirium tremens, acute hallucinosis, a fairly characteristic chronic delusional state, the polyneuritic psychosis, and alcoholic dementia. During the year ending September 30, 1913, 13.5% of all male admissions and 4.2% of all female admissions to the New York state hospitals were cases of alcoholic psychoses. This does not include cases which were not specifically alcoholic but in which intemperance was given as a contributing cause.

Syphilis.

4

Syphilis appears as the essential cause of all cases of general paresis and of cerebral syphilis (gummata, meningitides, etc.), and of a large proportion of the cases of cerebral arteriosclerosis.

Not

1 G. Aschaffenburg. Praktische Arbeit unter Alkoholwirkung. Kraepelin's Psychol. Arb., Vol. I, p. 608.

2 A. Smith. Ueber die Beeinflussung einfacher psychischer Vorgänge durch chronische Alkoholvergiftung. Br. ueber d. V. intern. Kongr. z. Bekämpf. d. Missbr. geist. Getränke, Basel, 1896, p. 341. 3 Kürz and Kraepelin. Ueber die Beeinflussung psychischer Vorgänge durch regelmässigen Alkoholismus. Kraepelin's Psychol. Arb., Vol. III, p. 417.

4 Twenty-fifth Annual Report of the State Hospital Commission, Albany, N. Y., 1914.

counting cases of the latter condition, which are not always of syphilitic origin, 19.4% of all male first admissions and 7.0% of all female first admissions to the New York state hospitals during the year ending September 30, 1913, occurred on the basis of syphilis as an essential cause.1

Head Injuries. The more important mental disorders occurring as result of head injuries are: traumatic delirium, traumatic neurasthenia, traumatic epilepsy, and traumatic dementia. These cases are far more often brought to general hospitals than to hospitals for the insane for reasons that are sufficiently obvious. Thus only 0.6% of all first admissions to the New York state hospitals during the year ending September 30, 1913, were cases of traumatic psychoses.1

§ 2. INCIDENTAL OR CONTRIBUTING CAUSES.

The incidental or contributing causes are remarkable for their multiplicity and complexity; one might almost say that they are as many as there are individual cases and that in no two cases is their manner of action exactly alike. In themselves, however, they do not suffice to produce insanity, but acquire pathogenicity only in the presence of an essential cause.

Some are met with in practice with special frequency and therefore seem to possess quasi-specific potency in the production of mental disorders.

Alcoholism, which has been already mentioned as

1 Twenty-fifth Annual Report of the State Hospital Commission, Albany, N. Y., 1914.

an essential cause, may also act as a contributing cause in the presence of a predisposition created by one of the other essential causes. Thus, acting on a basis of bad heredity, alcoholism may determine the development of dementia præcox or of a manic-depressive or an epileptic attack; and some hold that a syphilitic subject who is also intemperate is more likely to develop general paresis than one who is abstinent. Thus, of the 15.2% of first admissions to the New York state hospitals during the year ending September 30, 1913, which were attributed to alcoholism, only 9.4% were cases of specifically alcoholic psychoses, the remaining 5.8% being cases in which alcoholism played the part merely of a contributing

cause.

Head injuries, like alcoholism, are probably capable of acting not only as essential but also as contributing causes, especially as factors in the etiology of general paresis; their importance in this connection will be again discussed in the chapter devoted to this psychosis.

For the rest, recent studies seem to indicate that the incidental or contributing causes that are met with are psychic rather than physical in their nature or manner of operation.1

Even such causes as pregnancy, abortion, childbirth,

1 Adolf Meyer. The Role of the Mental Factors in Psychiatry. N. Y. State Hosp. Bulletin, N. S., Vol. I, 1908, p. 262. —Jung. The Psychology of Dementia Præcox. English translation by Peterson and Brill, New York, 1909. - A. J. Rosanoff. Exciting Causes in Psychiatry. Amer. Journ. of Insanity, Vol. LXIX, 1912, p. 351. – August Hoch. Precipitating Mental Causes in Dementia Præcox. Amer. Journ. of Insanity, Vol. LXX, 1914, p. 637.

and lactation are found in the better analyzed cases to act not as physical causes but through psychic accompaniments, such as illegitimacy, increasingly hopeless domestic infelicity, apprehension of added hardships; although it is undoubtedly also true that such conditions as febrile or exhaustion deliria may be produced by these causes acting in a physical way, especially in the presence of complications like excessive hemorrhage or infection.

Among the plainly psychic causes may be mentioned the following as being the more common: Business troubles: financial difficulties loss of employment, inability to get employment, failure in school examinations. Domestic troubles: abuse by husband, infidelity of husband, intemperance of husband, desertion, other conditions of marital infelicity. Love affairs: disappointment in love, unrequited love. Death or illness of relatives.

Perhaps in half the cases represented in state hospital statistics no exciting cause is given. In some of these cases this is due merely to the histories being incomplete, and in these the fact that no causes were assigned does not prove that none were to be found; but in most cases the ordinary data are on record and the fact is that neither the patients nor their relatives were able to discern in the conditions of existence anything that could be regarded as a pathogenic influence. Yet it is not probable that the mechanisms of the development of the psychoses in these cases differs essentially from that of the cases with a definitely assigned cause. When some striking occurrence in the environment of a patient is