Psychiatry

PSYCHIATRY, a special branch of medical science dealing with the causes, symptoms, course and treatment of disorders and diseases of the mind. The ultimate aim of this branch of medicine should be to ascertain the best means to promote normal thought and action individually and collectively, and to apply the knowl edge so obtained to the causation and prevention of mental de fects, disorders and diseases. See ABNORMAL PSYCHOLOGY; PSYCHOSIS, etc.

The causes of mental disorders and diseases are never single, but they naturally fall into two great groups : (I) Endogenous (from within) and (2) Exogenous (from without). They may be somatic, psychical or social. The hereditary factor is the most important endogenous cause.

The Endogenous Factor of Mental Disorders.

The life of the individual begins at the moment of conception, i.e., at the con jugation of the male and female germ cells. The raw material of character is a complex of inherited tendencies and dispositions impressed upon the individual by sex, species, race and ancestry, giving each individual a specific predetermined plasticity to re ceive and store stimuli and react to them in a particular way. Like tends to beget like—as Galton's History of Similar and Dissimilar Twins shows, in the dispositions and temperaments of the offspring.

A well-balanced mind is due to an inherent equipoise of the latent potentialities of character, and its efficient activity depends upon the potential psychophysical energy derived from the parental stocks. The study of heredity (I) by statistics, (2) by pedigrees and (3) by experience shows the importance of this factor in the causation of the true insanities which are not due to organic brain disease, where chance counts for everything and heredity for little or nothing. The raw material of mentality is conditioned by the innate potentialities of the fertilised ovum as it starts its course in life. At later stages of development, the fertilised ovum is influenced by pre-natal and post-natal exoge nous environmental factors in addition to the hereditary factors.

Pre-natal Exogenous Factors.

Much may happen while the embryo is developing in the mother's womb. Owing to abnormal conditions of growth, interfering with the circulation and nutri tion of the great brain, various degrees of arrest of development of the highest and latest evolutional structures of the brain may occur, viz., the cerebral hemispheres, which by their size especially distinguish the brain of man from the lower animals, and to which he owes his superior intelligence, may suffer from various con genital effects. (See INSANITY.) Likewise prolonged labour or

unskilful use of instruments may damage the brain and arrest growth.

Hereditary Factors.

Study of the hereditary factor in psy choses and psychoneuroses by the construction of a large number of pedigrees extending to three, four and five generations with collaterals, and by a card system of 4,000 relatives who were or who had been in the London County Council asylums, proves that heredity plays a very important part in neuroses and psychoses.

Neuroses may be classified as follows: (I) hysteria, (2) neurasthenia, (3) obsessional psychasthenia, (4) epilepsy and (5) migraine ; and psychoses as (I) paranoia (systematised delusional insanity), (2) dementia praecox, (3) manic-depressive insanity, of which there are several types, viz.: alternating periods of ex citement and depression (folie circulaire) and recurrent periods of maniacal excitement or of melancholic depression, alternating with periods of sanity, (4) involutional melancholia occurring at the climacterium in women, also in men between the ages of 55 and 65, though less frequently met with than in women. Both the latter forms of mental disorder may terminate in dementia.

These three last-named types are in some ways related to one another, and their onset is associated with the maturation or waning of the sex instinct. An involutional melancholic or senile dement may have offspring in whom manic-depressive insanity or dementia praecox may occur in adolescence, or a parent with manic-depressive insanity may have one or more offspring with dementia praecox. This phenomenon together with the fact that not infrequently several members of the same co-fraternity suffer with either dementia praecox or manic-depressive insanity or an atypical form, coming on at puberty or adolescence, at about the same age, shows antedating and hereditary predisposition as the important factor. There may be atypical cases in some respects resembling both these forms of mental disease, and it is a matter of opinion to which category a particular case should belong. This shows how fallacious classifications may be. The many changes which Krapelin has made in his classification emphasise the fact that each case must be regarded as a biological problem with two factors to consider, viz. : what an individual was born with; and what happened after fertilisation of the ovum—that is, pre-natal and post-natal conditions. There is, it seems, a causal correspondence in these three types of insanity connected with the "life reaction" of the primal instinct of propagation.