INTRODUCTION.

PSYCHIATRY is that branch of neurology which treats of mental disorders and of the organic changes associated with them.

Mental disorders arrange themselves in two fundamental categories, characterized respectively by insufficiency and perversion of the intellectual or moral faculties.

Insufficiency may be either congenital or acquired. In the first case it constitutes arrest of development; in the second, psychic paralysis. When the psychic. paralysis is temporary, causing a suspension, but not a destruction, of mental activity, the name psychic inhibition is applied to it; on the other hand, when it is permanently established, it constitutes mental enfeeblement or dementia.

Perversion of the intellectual and moral faculties may also be congenital or acquired. Various terms are applied to its manifestations, depending upon the particular function affected: hallucinations, delusions, morbid impulses, etc.

Mental diseases or psychoses are affections in which mental symptoms constitute a prominent feature. They differ from such mental infirmities as idiocy, moral insanity, and many states of dementia, in that they are expressions of active pathological processes

and not of permanent and fixed alterations of the mind.

Psychic infirmity, when not congenital, occurs as the outcome of mental disease. The relation between the two conditions is analogous to that which exists between ankylosis of a joint and the arthritis which produced it; the latter is a disease, the former an infirmity.

Two general terms still remain to be defined: mental alienation and insanity. Although they are often employed indiscriminately, their meaning is not quite identical.

Etymologically, an alienated (Lat. alienus) individual is one who has become "estranged" from himself, who has lost the control of his mental activity, who, in other words, is not responsible for his acts. This definition rests upon the metaphysical conception of a free will and cannot find a place in medical science, which must be based on observation and must adhere to demonstrable facts.

It is better to adopt an essentially practical definition, as has been done by most modern psychiatrists, and to designate by the term mental alienation the entire class of pathological states in which the mental disorders, whatever their nature be otherwise, present an anti-social character. Not every individual suffering from a psychic affection is alienated. This term can be applied only to those who, on account of some mental disease or infirmity, are likely to enter into conflict with society and to find themselves, in consequence, unable to be an integral part of it.

Insanity, as a scientific term, is falling into disuse and now retains a significance mainly as a legal one. Like lunacy it seems destined to become obsolete. For the present it would be best to restrict its application to cases in which the mental disorder is of such a nature as to render advisable commitment for treatment or custody to a special institution. Thus, according to the law of the state of New York, an . imbecile, an epileptic, or a senile dement ("dotard") is not insane unless he presents, in addition to the underlying infirmity, such manifestations as attacks of excitement or depression, hallucinations, or delusions; similarly, some cases of hysteria, neurasthenia, cerebral arteriosclerosis, or brain tumor may be declared "insane" and committed to an institution, and others not, depending on their manifestations.

This MANUAL is divided into two parts. The first part treats of general psychiatry and comprises a study of the causes, symptoms, treatment and prevention of mental disorders, considered independently of the affections in which they are encountered. The second part is devoted to special psychiatry, that is to say, to the study of individual psychoses.

It has been thought advisable to devote a good deal of space to general psychiatry, at least relatively to the size of the whole book. A precise if not an extensive knowledge of the more important elementary psychic disorders would seem to be altogether indispensable for an understanding of the genesis and evolution of the psychoses.

MANUAL OF PSYCHIATRY.

PART I.

GENERAL PSYCHIATRY.

CHAPTER I.

ETIOLOGY.

"ON studying closely the etiology of mental diseases one soon recognizes the fact that in the great majority of cases the disease is produced- not by a particular or specific cause, but by a series of unfavorable conditions which first prepare the soil and then, by their simultaneous action, determine the outbreak of insanity."

This was written nearly three-quarters of a century ago. To-day, though this view is still held to a certain extent, we are nevertheless able to distinguish amongst the many causes some few that are essential from others that are merely incidental or contributing. In addition there are other factors that have to do with the etiology of mental disorders, especially, race, age, sex, environment, occupation, marital condition, education, and immigration.

1 Griesinger. Die Pathologie und Therapie der Geisteskrankheiten.