PSYCHOSES The most important of the psychoses in childhood are those which are associated with defective intelligence—so called defect psychoses. Among these the active congenital conditions which are included under the general term of "imbecility" are much more frequent than acquired dementia.
Congenital defect psychoses are peculiar inasmuch as they usual ly represent the symptoms of an organic brain lesion and are therefore permanent, irreparable anomalies.
An exception to this is found in one group of congenital defect psychoses which is produced by disturbances of the function of the thyroid gland—cretinism and niy.ridiocy in its various forms, which are sus ceptible to organotherapeutic treatment and therefore not caused by an anatomic brain lesion. As these conditions, including mongolism which from the viewpoint of differential diagnosis belongs in the sante group, have been described in connection with diseases of the thyroid giand, all that remains to be added here is a short description of one symptom, namely, the impairment of intellect, without regard as to whether it is associated with other symptoms or constitutes the entire clinical picture.
We distinguish three degrees according to the severity of the dis turbance; idiocy, imbecility in the narrower sense, and feeble-mindedness (debility). The lines of division are by no means sharp. Alxence of attention is said to be characteristic of the idiot, while the ability to follow quite a complicated train of thought with a preponderance of ethical deficiency is usually said to be the distinguishing mark of the feeble-minded.
There is never any difficulty in recognizing idiocy, at least after the first few months of life. The absence of reactions to impressions from the environment that indicate the awakening of the mind is proof enough.
In the case of imbeciles greater difficulty is experienced because, in the beginning at least, the absence of reactions is not complete and there is simply delayed psychic development. While it is possible in an imbecile infant of about six months to attract the attention by making a noise, by holding up bright objects and other similar methods, the attention cannot be fixed because the new impression fill& no acquired impressions with which to associate itself and accordingly fails to arouse any interest. Hence, these children, although their muscles are well developed, do not hold their heads up nor grasp things nor laugh, and are late in learning the coordinated movements of sitting, standing and walking. Even with the greatest care it is often impossible to train them to cleanliness until the third year or later.
Another very important early symptom, which is also explained by the absence of attention, is the diminution of the pain sense. The
sense of taste is often so greatly reduced that the children will swallow sour and bitter solutions without making a face. In itself, however, the disturbance of taste is not as conclusive a proof of imbecility as is hypalgesia, because it aiS0 occurs in children who arc not imbeciles but are suffering from chronic rachitic disturbance (rachitis) during the first two years of life. While the positive demonstration of hypalgesia and hypogeusia are exceedingly valuable, the absence of these anomalies is by no means proof that the child is psychically intact. Moreover, there is no constant relation between the disturbances of pain and taste and the degree of the mental impairment in other respects.
As the child becomes older the next most important criterion, the development of the faculty of speech, becomes manifest.
While a child with normal mentality begins to speak at the age of about eighteen months, unless its development has been greatly delayed by disease, an imbecile often does not begin until it has reached the age of three or four years, and its progress is very much slower than that of a healthy child. Again, however, there is no strict parallelism between the development of the speech faculty and mental impairment. Some children begin to speak at the normal timc and niake fairly good progress; while, conversely, in children with mental impairment so slight that it is overlooked for a long time or possibly overestimated, the disturbance of speech appears to be merely an isolated aphasic disturbance (word deafness). In cases of this kind the child understands what is said very well for some time; but while in the normal child this stage is shortly followed by the actual ability to speak, that power is developed very late and very slowly and the chikl apparently never learns to speak properly. The same disproportion as between speech and intellect in general is often found between thc various other intellectual faculties. Gross defects in one or more departrnents of intellectual activity may be associated with normal or even unusually good development in others; for example, a feeble-minded child may be very good at arithmetic because it possesses an unusual and overdeveloped memory for rill rinbers; another inay be musical; a third an unusually clever actor and entertain the othcr children by the performance of all kinds of tricks. Another type that is quite common in institutions for the feeble-minded is seen in those children who learn to write and read without any difficulty but have no idea whatever of numbers and, after years of schooling, are barely able to do a simple sum in arithmetic involving no more than the addition of numbers up to ten, or even to count the fingers.