The most interesting and important feature, perhaps, of Kraepelin's presentation is his insistence upon internal causes only as etiological factors. He assumes a psychopathic foundation for the development of the disease. In more than one half of his cases he found well marked personal peculiarities. These were manifested in some instances in the form of irritability, excitability and abnormalities of conduct. Other individuals were suspicious, unreliable, lacking in will power and over-ambitious. Homosexual tendencies were not infrequent. External factors, such as unpleasant experiences, may influence the form of the delusional expressions but should not be looked upon as explaining their origin. They develop in an emotional soil definitely related to the hopes and fears of the healthy individual and are to be looked upon as a morbid transformation of perfectly normal mechanisms. In addition to this he speaks of an increased self-consciousness, a natural tendency to resistiveness, an undeveloped type of thinking, psychological compensations for the disappointments of life, evidences of developmental inhibitions, improper habits of thought leading to morbid conceptions, etc. He refers to exaggerated self-consciousness as the fundamental basis of paranoia. In this soil delusions develop as a result of inadequate intellectual processes due to developmental inhibitions. All of these views have been elaborated more fully in his recent discussions of the subject of "comparative psychiatry."[321] These mechanisms, he says, have not escaped the notice of the Freudian school. Kraepelin feels, however, that their arguments "are not based either on a clear conception of paranoia or on any evidence at all acceptable."
Bleuler's theory of the disease is summed up in the following quotation from his "Affectivität, Suggestibilität, Paranoia"[322]:—"The exact observation of the objective and subjective relations at the time of the origin of the disease shows us therefore nothing more than the appearance of errors, such as occur to normal persons under analogous affects and a connection of accidental occurrences to a thought complex which is kept continually awake by defects and his own trends of thought, just as it is in a corresponding normal mental process. The pathological feature is only the fixation of the error so that it becomes a delusion, and then the further extension of the delusions so that it finally becomes paranoia." In 1906 when this was written he suggested no explanation for the extension of such errors and their fixation in an actual psychosis. This might readily be interpreted as a logical result of the paranoic "constitution."
The development of paranoic states was summarized by Meyer [323] as follows:—" a. Feeling of uneasiness, tendency to brooding, rumination and sensitiveness, with inability to correct the notions and to make concessions—paranoic constitution and paranoic moods. b. Appearance of dominant notions, suspicious or ill balanced aims. c. False interpretations with self-reference and tendency to systematization, without or with d. Retrospective or hallucinatory falsifications, etc. e. Megalomanic developments or deterioration or intercurrent acute episodes. f. At any period antisocial and dangerous reactions may result from the lack of adaptability and excessive assertion of the sidetracked personality."
Freud sees in paranoia a reversion to the homosexuality of the developmental period of the individual with a projection of symptoms resulting from mental conflicts due to a repression of complexes. He described the sexuality of the infantile period as being purely autoerotic in character, the sexual interests of the child being centered in its own body. From this stage the object of interest is gradually transferred to other individuals of the same sex, the normal attraction to the opposite sex being a final development of later years. Freud believes that in paranoia there is a fixation in one of these early transitional stages. "Persons who cannot rise completely out of the stage of narcissism and are thus prematurely fixed or arrested in the evolution of their dispositions, are exposed to the danger that a flood of libido which finds no outlet, sexualizes their social tendencies and reverts the sublimations achieved in the course of the development."[324] The resulting mechanisms may be looked upon as defense reactions. The subconscious homosexual longings of the individual are repressed but finally admitted to full consciousness in the form of a projection, the sexual object usually being accused of persecution, thus justifying the attitude of the paranoic towards the cause of his troubles. In erotomania the antagonism is directed not against the homosexual object but upon some person of the opposite sex. Freud interprets the delusions of jealousy of the alcoholic as an evidence of homosexual attraction, the individual justifying himself by the charge that it is his wife and not himself who is the guilty one. The delusions of grandeur he looks upon as a sweeping denial of all extraneous influences, the individual building a defense for himself by assuming a self-aggrandizement that leaves no room for homosexual objects. Perhaps these mechanisms are, as Meyer suggests, only another expression of the well recognized and more or less normal tendency to accuse others of being at fault in some way when what we do ourselves goes wrong. Certainly, if nothing more, they are exceedingly ingenious and interesting theories. One cannot but be impressed by the extraordinary skill of Freud in discovering the sexual origin of almost any mental process with which we are familiar. The ready facility with which his study of sexual conflicts and repressions can be shown to serve as a complement to the anatomical, symptomatic, and prognostic hypotheses of Kraepelin is also worthy of note.
As has already been said, there is considerable question as to how much, if anything, remains of the old-time paranoia concept. The uncertainties attending diagnosis have given rise to the modifying term "paranoid" which has been very generally used for many years. It should be remembered that paranoia when at its best only constituted approximately two per cent of all psychoses reported from institutions. These various considerations have resulted in its not having a distinctive place in the classification adopted by the American Psychiatric Association and it has been given official recognition as follows:—
"From this group should be excluded the deteriorating paranoid states and paranoid states symptomatic of other mental disorders or of some damaging factor such as alcohol, organic brain disease, etc.
"The group comprises cases which show clinically fixed suspicions, persecutory delusions, dominant ideas or grandiose trends logically elaborated and with due regard for reality after once a false interpretation or premise has been accepted. Further characteristics are formally correct conduct, adequate emotional reactions, clearness and coherence of the train of thought."
A study of the statistics of American hospitals shows quite clearly the importance which should be attached to the paranoid conditions. During 1918 and 1919 there were 13,588 admissions to the thirteen New York state hospitals. Two hundred and fifty-six, or 1.88 per cent, of these were cases of paranoia or paranoid conditions. During a period of eight years there were 49,640 admissions of which 1,240, or 2.5 per cent, were paranoid conditions. In Massachusetts sixty-four, or 2.12 per cent, of the 3,011 admissions during 1919 were reported as paranoid conditions. In twenty-one hospitals in other states there were 18,336 admissions. Of these, 789, or 4.3 per cent, were paranoid conditions. These statistics show quite a small admission rate for these psychoses in New York and Massachusetts. The rate in other state hospitals is noticeably higher. As the percentage for dementia praecox is considerably lower in the reports from these institutions than it is in Massachusetts and New York, it is fairly reasonable to assume that many cases shown as paranoid forms of dementia praecox in Massachusetts and New York are classified with the paranoid conditions in the other states. If we consider the total admissions from all of the hospitals in question, we find 2,093 paranoid conditions in all, constituting 2.94 per cent of a total of 70,987 cases. It has already been shown that paranoia, at a time when it was a well recognized entity, constituted only 1.9 per cent of over eighty-four thousand consecutive admissions. This clinical grouping has, therefore, obviously been enlarged by adding paranoid conditions which could not probably be classified as well recognized types of other psychoses.