Table of Contents
DELUSIONS do not belong to the domain of functional psychology, but deserve our consideration, because they fall on the borderland of psychopathic states. A delusion is conceptual in its nature. One may have an illusion or hallucination and still be perfectly sane. He may attempt to verify it by one of the two or both criteria and, finding it false, refuse to give assent to its external reality or objectification. It is only when one gives assent to his illusion or hallucination, that is, when he believes that it really exists externally, it is only then that it becomes a delusion. To give an example,—There may be paraesthesia in one's hand. The member may feel like putty or glass. This in itself may be considered an illusion. The patient attempts to verify it with his other senses, tries to show it to other people, his physician for instance, and failing to confirm it, then simply regards the feeling as subjective. But if the patient, in spite of all verification with negative results, and social objections and assurances and arguments by his fellow-men, should give assent or still confirm the objectification of his illusion or hallucination, then it would constitute a delusion characteristic of insanity.
To give another example, if a man has an hallucination or illusion that he has seen something like a mermaid, it is a delusion when he gives his assent to it and affirms that it really exists. In short, the man who has an illusion or hallucination is correct subjectively. He is only wrong when he objectifies it, and then it becomes a delusion. The patient may have the hallucination of hearing a voice; it becomes a delusion, if he objectifies the voice and thinks some one is addressing him.
Delusion can be defined only in social terms. Man is essentially social in nature and living in a certain social environment, he may maintain certain ideas and do certain things, which under other social conditions would be considered as non-adaptations. Thus for instance, a man performing an Australian dance in a public thoroughfare of some civilized city would be promptly examined as to his mental state, while an Australian savage performing the same feat in his own country would not be regarded as abnormal, because the actions are adapted to his social environment.
The same holds true with regard to ideas and beliefs. A delusion, therefore, may be defined as a false belief which may lead to actions, out of accord with the social environment. This, however, does not entirely constitute the insane delusion. Another factor of the insane delusion is the impossibility of changing or correcting the erroneous beliefs, even though the lack of adaptation is pointed out and made perfectly obvious. An insane delusion, therefore, may be defined as a persistent, incorrigible, unsocial, erroneous belief.
Although an assent given to an hallucination or illusion constitutes a delusion, not all delusions are necessarily accompanied by illusions or hallucinations. All of the perceptions may be quite correct and the patient may still have a false belief in his formation of judgment about the perceptions. Thus for example, a man may in reality hear whispering or conversation, but the interpretation of the whispering and talking may be incorrect, that is he may believe that all of them relate to himself, such as conspiracies to injure him, in spite of the general assurance and evidence by his friends that nothing of the sort exists. Here then the sensory criterion cannot be used since the man is quite correct in his impressions. It is only when the social criterion is applied that he is found to be insane.
The general definition of delusion, therefore, may be expressed as a persistent, incorrigible, individualized, false belief, either in regard to self or environment, or their interrelation. An insane delusion differs from the sane delusion which may be maintained by the members of a whole society. Thus, for instance, in the middle ages, people who became ill, explained their illness as the result of witchery, were perfectly normal persons, because this was the general belief, although false, of the age. But if to-day a civilized man should make any such claim and persist in his belief, he would be suffering from an insane delusion. Since delusions are false beliefs in regard to adjustments of external to internal relations, they may be classified, with Mercier, as due to:
1. Delusion in regard to change in environment.
2. Delusion in regard to change of self.
3. Delusion in regard to change of adjustment of self to environment.
Delusion in regard to environment may be of illusory or hallucinatory character, or incorrect belief as to the external environment. For example, a man may regard a clock in his room as an animal and constantly treat it as such. Or he may have an hallucination of angels or devils and then believe that he is having conversations with them.
The incorrect interpretation of the external environment is illustrated by those who have the delusion that they are in some strange country surrounded by a foreign people and will make attempts to speak the foreign language.
Delusion in regard to change of self may be either partial when for example, the patient believes a part of his body is made of some material, such as wood or glass, or it may be complete, when, for instance, the patient believes that the entire body is changed.
Delusion in regard to change of adjustment of self to environment is well illustrated in delusions of grandeur, persecution, megalomania, or micromania, etc. In delusions of grandeur the subject considers himself better or richer than he is, or may think himself some great personage, the Saviour, or God Almighty, etc.
Delusions may again be divided into (1) systematized; and (2) unsystematized.
1. A systematized delusion is an organized system of mental states of which an erroneous belief or delusion forms the center. The patient brings the different impressions coming from the external world in logical relation to some one erroneous belief that has complete possession of him. The belief seems to form a mental eddy in which all external impressions are caught; the whole mental life of the patient becomes crystallized about this false idea. He may, for instance, consider himself a messiah; he will behave in accordance with this belief, live up to it, dress accordingly, and no matter what he sees or hears he will in some way relate it to his messianic mission.
2. An unsystematized delusion is one in which a false belief is entertained, but there are at the same time maintained other beliefs and other impressions, which are in direct opposition to the delusion. The patient makes no attempt to bring his various sensations and perceptions in accord with his delusion. Such delusions we find for example in dementia paralytica, dementia praecox, and other cognate conditions. The patient, for instance, may consider himself a thousand miles in height. It may be pointed out to him that his neighbor is only six feet tall. He will agree that his neighbor is tall and that he himself is shorter. But when at once asked how tall he is, he will again reply that he is a thousand miles high. In short, he fails to harmonize the rest of his perceptions and ideas with his delusion.