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All writers on this subject confess their inability to frame a strictly logical or a completely satisfactory definition. The dividing line between sanity and insanity, like the line that distinguishes a man of average height from a tall man, can be described only in terms of a moral estimate. There is a borderland between the two states which is not easily identified as belonging certainly to either. Hence a definition that aims at rigorous comprehensiveness is liable to include such non-insane conditions as hysteria, febrile delirium, or perverted passions. The definition given by the "Century Dictionary" is probably as satisfactory as any: "A seriously impaired condition of the mental functions, involving the intellect, emotions, and will, or one or more of these faculties, exclusive of temporary states produced by and accompanying intoxications or acute febrile diseases."

Not less difficult is the problem of classification. No classification based on a single principle is entirely satisfactory. Anatomical changes are an inadequate basis because they are absent from many forms of insanity; the causes are so numerous and so frequently combined in a single case that it is impossible to say which is predominant; and the symptoms are so manifold that the accidental cannot always be distinguished from the essential. Indeed, the nervous system and the mental functions are so complex and so inadequately known that any attempt at an accurate classification of their abnormal states must of necessity be a failure. In this article only the most important forms will be enumerated, namely, those which are most prevalent and those which are clearly distinguished from one another.

One of the oldest divisions of mental disorders is into melancholia and mania. In the former the dominant mood is depression; in the latter, exaltation. The former differs from sane melancholy only in degree, and its chief characteristics are mental anguish and impulses to suicide. It includes probably one-half of all the cases of insanity, and is more frequently cured than any other form. In mania the morbidly elated mood may vary from excessive cheerfulness to violent rage. Monomania, which may exhibit characteristics of both melancholia and mania, is a perversion of the intellective rather than the affective faculties. Its chief manifestation is delusions, very frequently delusions of persecution. Monomania corresponds roughly to the later and more precise term paranoia. In this form the delusions are systematized and persistent, while the general intellectual processes may remain substantially unimpaired. When the attacks of melancholia or mania occur at regular intervals they are frequently named periodical insanity. The term partial insanity comprises chiefly those varieties known as impulsive, emotional, and moral. These are characterized by a loss of self-control, on account of which the patient performs acts that are at variance with his prevailing disposition, ideas, and desires—for example, murder and suicide. Somewhat akin to these forms are those associated with such general diseases of the nervous system as epilepsy, hysteria, and neurasthenia. When insanity takes the form of a general enfeeblement of the mental faculties as a consequence of disease, it is called dementia. It is usually permanent. Its principal varieties are senile, paralytic, and syphilitic. Paresis is one kind of paralytic dementia. All the above-mentioned forms of insanity are acquired, in the sense that they occur in normally developed brains. Congenital insanity, or feeble-mindedness, is divided chiefly, according to its degrees, into imbecility, idiocy, and cretinism.

That insanity is on the increase, seems to be the general verdict of authorities, although the absence of reliable and comprehensive statistics makes any satisfactory estimate impossible. Whatever be its extent, the increase is undoubtedly due in some measure to our more complex civilization, especially as seen in city life. In general, the causes of insanity may be reduced to two: predisposing causes and exciting causes. The most important of the former are insane, neurotic, epileptic, drunken, or consumptive ancestors; great stress and strain, and a neuropathic constitution. Among the exciting causes must be mentioned shock, intense emotion, worry, intellectual overwork, diseases of the nervous system, exhausting diseases, alcoholic and sexual excesses, paralysis, sunstroke, and accidental injuries. It has been estimated that the physical causes, whether predisposing or exciting, stand to the moral causes, such as affliction and losses, in the ratio of four to one. Of 2476 cases due to physical causes which were admitted to the asylums of New York during the twelve months preceding 30 September 1900, alcoholic and sexual excesses and diseases had brought on 684. The majority of cases of insanity, however, are traceable to more than one cause.

Inasmuch as insanity almost always involves some perversion of the will, either direct or indirect, it raises interesting and important questions concerning moral responsibility. Every impairment of mental function must impede the freedom of the will, either by restricting its scope, or by diminishing or destroying it outright. Ignorance, error, blinding passion, and paralysing fear all render a person morally irresponsible for those actions which take place under their influence. This is true even of the sane; obviously it happens much more frequently among the insane, owing to delirium, delusions, loss of memory, and many other mental disorders. Is it, however, only in this general way, that is, through defective action of the intellect, that freedom and responsibility are lessened or destroyed in persons who are of unsound mind? May not the disease act directly upon the will, compelling the patient to do things that his intellect assures him are wrong? The English courts and almost all the courts of the United States answer this question in the negative. Their practice is to regard a defendant in a criminal case as responsible and punishable if at the time of the crime he knew the difference between right and wrong, or at least knew that his act was contrary to the civil or moral law. For example, a man who, labouring under the insane delusion that another has injured his reputation, kills the latter is presumed to be morally accountable if he realized that the killing was immoral or illegal. In a word, the rule of the courts is that knowledge of wrong implies freedom to avoid it. Medical authorities on insanity are practically unanimous in rejecting this judicial test. Experience, they maintain, shows that many insane persons who can think and reason correctly on every topic except that which forms the subject of their delusion are unable to determine their wills and direct their actions accordingly. In an unsound mind normal intellection is not always accompanied by normal volition. We should expect to find this true from the very nature of the case. For if a diseased brain can interfere with normal thinking it can undoubtedly interfere likewise with normal willing. And there is in the nature of the situation no reason why this deranged condition of the will may not manifest itself in connexion with normal, as well as with abnormal, intellectual action. To assume that the victim of an insane delusion has perfect control over those actions that are apparently not affected by the delusion—actions that he clearly perceives to be wrong, for example—is to assume that the operations of intellect and will are as perfectly harmonized in an unsound as in a sound mind. As a matter of fact, the presumption would seem to lead the other way, that is, to the conclusion that the action of the will as well as that of the intellect will be abnormal.

Insanity experts do not, indeed, contend that all the consciously immoral acts of a partially insane person are unfree. They merely insist that these acts cannot be presumed to be free on the simple ground that the patient is aware of their immorality. In their view, the question of freedom and responsibility can be answered only through an examination of all the circumstances of the particular case. The laws of one American state, and of some foreign countries, are in substantial harmony with this doctrine. According to the laws of New York, "No act done by a person in a state of insanity can be punished as an offence." The French law is slightly more specific: "There can be no crime nor offence if the accused was in a state of madness at the time of the act." More specific still is the law of Germany, yet it does not introduce knowledge or advertence as a criterion of responsibility: "An act is not punishable when the person at the time of doing it was in a state of unconsciousness or disease of mind by which a free determination of the will was excluded".In passing it may be observed that the laws of all countries assume that freedom of the will and moral responsibility are realities, and declare that punishment is to be inflicted only when the will has acted freely.

The discussion in the last two paragraphs refers especially to delusive insanity, or to what is sometimes called partial intellectual insanity. There is another variety which is even more important as regards the question of moral responsibility. Inasmuch as it involves the will and the emotions rather than the intellect, it is called affective insanity, and it is subdivided into impulsive and moral. According to medical authorities, impulsive insanity may occur without delusions or any other apparent derangement of the intelligence. Those suffering from it are sometimes driven irresistibly to commit actions which they know to be wrong, actions which are contrary to their character, dispositions, and desires. Many suicides and homicides have in consequence of such uncontrollable impulses been committed by persons who were apparently sane in all other respects. Obviously, they were not morally responsible for these crimes. Although this theory runs counter not only to English and American legal procedure, but also to the opinions of the average man, it seems to be established by the history of numerous carefully observed cases, and to provide an explanation for many suicides and murders that are otherwise inexplicable. Moreover, it is inherently probable. Since insanity is a disease of the brain which may affect any of the mental faculties, there seems to be no good reason to deny that it can affect the emotions and the will almost exclusively, leaving the intellectual processes apparently unimpaired. The theory does, indeed, seem to disagree with the doctrine of our textbooks of moral philosophy and theology, which maintains that freedom of the will can be diminished or destroyed only through defective or confused action of the intellect. There is, however, no real opposition except on the assumption that the will and intellect in a diseased mind co-operate and harmonize as perfectly as in a mind that is sane. In the latter the will has power to determine itself in accordance with the ideas and motives presented by the intellect; in the former this power may sometimes be lacking. The inference from intellectual advertence to volitional freedom may, as noted above, be valid in the one case, and quite invalid in the other. This consideration is manifestly of great importance in determining whether a suicide is worthy of Christian burial. If he is afflicted with ideational or impulsive insanity, the mere fact that his intelligence seemed to be normal, and all his acts deliberate, at the time of his self-destruction, is not always conclusive proof of volitional freedom and moral guilt. In what is called moral insanity there is sometimes the same lack of self-control as in impulsive insanity, together with a perversion of the feelings, passions, and moral notions. It constitutes, therefore, an additional obstacle to freedom in so far as it interferes with normal intellectual action through abnormally strong passions and false ideas of right and wrong. Obviously, however, the mere fact that the affections, passions, or moral notions are perverted, for example, with regard to sexual matters, is not always evidence of true insanity, still less of that variety of insanity that directly hampers freedom of the will.

Adults who have always been insane can receive baptism, since, as in the case of infants, the Church's intention supplies what is lacking. If they have ever been sane, they can be baptized when in danger of death or or if incurable, provided they had when sane a desire for the sacrament. The insane cannot be sponsors at baptism. They may receive confirmation. Communion should not be given to those who have always been insane. Those who, before becoming insane, were pious and religious, should be given Communion when in danger of death. When there are lucid intervals, Communion may then be administered. The same applies to extreme unction. In Holy orders, insanity is an irregularity under the head of defect. A candidate temporarily insane through some transient and accidental cause may, after recovery, be ordained. One deranged after ordination may exercise his orders, if he regains his sanity. The perpetually insane cannot marry. But "if the patient has lucid intervals, the marriage contracted during such an interval is valid, though it is not safe for him to marry on account of his inability to rear children." (St. Thomas, In IV Sent., dist. xxxiv, q. i, art. 4.)


Conolly, Construction and Government of Lunatic Asylums (London, 1847); Bucknill and Tuke, Psychological Medicine (London, 1879); Hammond, Treatise on Insanity (New York, 1893); Maudsley, Responsibility in Mental Disease (New York, 1899); Church and Peterson, Nervous and Metal Diseases (Philadelphia, 1901); Walsh, The Popes and Science (New York, 1908); Esquirol, Des maladies mentales (Paris, 1838); Gaupp, Die Entwickelung der Psychiatrie im 19. Jahrhundert(Berlin, 1900); Brockhaus in Konversationslexikon, s.v. Irrenanstalten.

About this page

APA citation. Ryan, J.A. (1910). Insanity. In The Catholic Encyclopedia. New York: Robert Appleton Company.

MLA citation. Ryan, John Augustine. "Insanity." The Catholic Encyclopedia. Vol. 8. New York: Robert Appleton Company, 1910. <>.

Transcription. This article was transcribed for New Advent by Ronald N. Neff. Gratias ago Deo pro Victor T. Day and Ruth E. Day, grandparents.

Ecclesiastical approbation. Nihil Obstat. October 1, 1910. Remy Lafort, S.T.D., Censor. Imprimatur. +John Cardinal Farley, Archbishop of New York.

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