Any of a group of severe mental disorders that have in common symptoms such as hallucinations, delusions, blunted emotions, disorganized thinking, and withdrawal from reality. Five main types are recognized: the paranoid, characterized by delusions of persecution or grandeur combined with unrealistic, illogical thinking and frequent auditory hallucinations; the disorganized (hebephrenic), characterized by disordered speech and behaviour and shallow or inappropriate emotional responses; the catatonic, characterized by motor inflexibility or stupor along with mutism, echolalia, or other speech abnormalities; the simple or undifferentiated type, which conforms to basic definitions of schizophrenia but does not exhibit particular behaviours in the aforementioned types; and the residual type, which is a chronic stage indicating advancement toward later-stage schizophrenia. Schizophrenia seems to occur in 0.5–1percnt of the general population, and more than half of those so diagnosed will eventually recover. There is strong evidence that genetic inheritance plays a role, but no single cause of schizophrenia has been identified. Stressful life experiences may help trigger its onset. Treatment consists of drug therapy and counseling.
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The primary disturbance in dementia praecox is not one of mood (as is the case in manic-depressive illness), but of thinking or cognition. Cognitive disintegration refers to a disruption in cognitive or mental functioning such as in attention, memory, and goal-directed behavior.
From the outset, dementia praecox was viewed by Kraepelin as a progressively degenerating disease from which no one recovered. However, by 1913, and more explicitly by 1920, Kraepelin admitted that although there seemed to be a residual cognitive defect in most cases, the prognosis was not as uniformly dire as he had stated in the 1890s.
Morel described an entire category of psychotic disorders that ended in dementia, and as a result he may be regarded as the first alienist or psychiatrist to develop a diagnostic system based on presumed outcome rather than on the current presentation of signs and symptoms. Morel, however, did not conduct any long-term or quantitative research on the course and outcome of dementia praecox (Kraepelin would be the first in history to do that) so this prognosis was based on speculation. It is impossible to discern whether the brief description of the disorder described by Morel was equivalent to the disorder later called dementia praecox by Pick and Kraepelin. Nor is there any reason to conclude that either of these men used Morel as a source of inspiration for their concepts.
Together Kahlbaum and Hecker were the first to describe and name such syndromes as dysthymia, cyclothymia, paranoia, catatonia, and hebephrenia. Perhaps their most lasting contribution to psychiatry was the introduction of the "clinical method" from medicine to the study of mental diseases, a method which is now known as psychopathology.
Other than Morel’s description of his degeneration theory, the element of time had largely been missing from definitions of mental disorders. Psychiatrists made assumptions about prognosis that were not based on careful observation of the changing symptoms of patients over time. Psychiatrists and other physicians who wrote about the insane arbitrarily invented names for insanities and described their characteristic signs and symptoms based on a short-term, cross-sectional observation period of their lunatic patients.
When the element of time was added to the concept of diagnosis, a diagnosis became more than just a description of a collection of symptoms: diagnosis now also defined prognosis (course and outcome). An additional feature of the clinical method was that the characteristic symptoms that define syndromes should be described without any prior assumption of brain pathology (although such links would be made later as scientific knowledge progressed). Karl Kahlbaum first made his appeal for the adoption of the clinical method in psychiatry in his 1874 book on catatonia. Without Kahlbaum and Hecker there would be no dementia praecox.
Quantification helped to eliminate any subjective biases on the part of the researcher. He began the first such research program of this nature in the history of psychiatry at Heidelberg in 1891, collecting data about every new patient that was admitted to the clinic (not just interesting cases, as had been the case in the past) and summarizing them on specially prepared index cards, his famous Zahlkarten. He had been keeping data on such cards since 1887. In his posthumously published Memoirs (first published in German 61 years after his death) Kraepelin described his method:
. . . after the first thorough examination of a new patient, each of us had to throw in a note [in a "diagnosis box"] with his diagnosis written on it. After a while, the notes were taken out of the box, the diagnoses were listed, and the case was closed, the final interpretation of the disease was added to the original diagnosis. In this way, we were able to see what kind of mistakes had been made and were able to follow-up the reasons for the wrong original diagnosis (p. 61).
Kraepelin was obsessed with finding patterns in the data on these cards, at times taking them home with him or on vacation. In 1893, two years after starting his more rigorous research program in Heidelberg, the 4th edition of Kraepelin’s textbook, Psychiatrie, reflected some preliminary impressions derived from the analysis of his cards. Clinical syndromes involved not only a diagnosis according to signs and symptoms, but also included course and outcome. In that edition he introduced a class of psychotic disorders he called "psychic degenerative processes." Three of these came directly from the work of Kahlbaum and Hecker: dementia paranoides (a sudden-onset, degenerative form of Kahlbaum’s paranoia; catatonia (directly from Kahlbaum’s 1874 monograph on the subject); and dementia praecox, which was essentially Hecker’s hebephrenia (as described in 1871). Dementia precox was hebephrenia and would remain so in Kraepelin’s thinking for 6 more years.
In March 1896 the 5th edition of Kraepelin’s textbook appeared. In it, Kraepelin stated that he was confident of the value of his clinical method of using qualitative and quantitative data collected over a long period of observation of patients as a way of developing a diagnosis that included prognosis (course and outcome):
What convinced me of the superiority of the clinical method of diagnosis (followed here) over the traditional one, was the certainty with which we could predict (in conjunction with our new concept of disease) the future course of events. Thanks to it the student can now find his way more easily in the difficult subject of psychiatry.
In the 1896 5th edition, dementia praecox (still essentially hebephrenia), dementia paranoides, and catatonia are separate psychotic disorders included among "metabolic disorders leading to dementia."
The 8th edition of Kraepelin’s Psychiatrie was a four-volume opus, each of which appeared in different years between 1909 and 1915. In this edition dememtia praecox became one of the "endogenous dementias." It is in the 1913 third volume (second part) of this edition that Kraepelin adjusts his concept of prognosis to admit that a partial remission of symptoms occurred in approximately 26 percent of his patients.
This brought dementia praecox in line with Eugen Bleuler’s claims about schizophrenia, which he had insisted from the start (in 1908) that (a) in many cases there was no fateful progressive deterioration, that (b) in some cases the symptoms did indeed remit for periods of time, and (c) that there were cases of complete recovery.
The 8th edition of 1913 is also notable for the fact that Kraepelin increased the number of forms of dementia to 11. However, the three classical original subtypes would remain as the most influential description of this disorder for the century that followed. The 8th edition of Psychiatrie was that last Kraepelin would produce in his lifetime. He was working on a 9th edition with Johannes Lange (1891-1938) but died in 1926 before it could be completed. Lange finished the bulk of it and published it in 1927.
Adolf Meyer was the first to apply the new diagnostic term in America. He used it at the Worcester Lunatic Hospital in Massachusetts in the fall of 1896.
Both dementia praecox (in its three classic forms) and ‘manic-depressive psychosis’ gained wider popularity in the larger institutions in the eastern United States after being included in the official nomenclature of diseases and conditions for record-keeping at Bellevue Hospital in New York City in 1903. The term lived on due to its promotion in the publications of the National Committee on Mental Hygiene (founded in 1909) and the Eugenics Records Office (1910). But perhaps the most important reason for the longevity of Kraepelin’s term was its inclusion in 1918 as an official diagnostic category in the uniform system adopted for comparative statistical record-keeping in all American mental institutions, The Statistical Manual for the Use of Institutions for the Insane. Its many revisions served as the official diagnostic classification scheme in America until 1952 when the first edition of the Diagnostic and Statistical Manual of Mental Disorders, or DSM-I, appeared. Dementia praecox disappeared from official psychiatry with the publication of DSM-I, replaced by the Bleuler/Meyer hybridization ‘schizophrenic reaction.’
The reception of dementia praecox as an accepted diagnosis in British psychiatry came much slower, perhaps only taking hold around the time of the First World War. There was substantial opposition to the use of the term "dementia" as misleading, partly due to findings of remission and recovery. Some argued that existing diagnoses such as "delusional insanity" or "adolescent insanity" were better or more clearly defined. In France an older psychiatric tradition regarding the psychotic disorders predated Kraepelin, and the French never fully adopted Kraepelin’s classification system. Instead the French maintained an independent classification system throughout the 20th century. After 1980, when DSM-III totally reshaped psychiatric diagnosis, French psychiatry began to finally alter its views of diagnosis to converge with the North American system. Kraepelin thus finally conquered France via America.
The term "schizophrenia" was first applied by American alienists and neurologists in clinical settings around the year 1918. It is first mentioned in The New York Times in 1925. Until 1952 the terms dementia praecox and schizophrenia were used interchangeably in American psychiatry, with occasional use of the hybrid terms "dementia praecox (schizophrenia)" or "schizophrenia (dementia praecox)."
Vol. VII: Kraepelin in Munich, Teil II: 1914-1926 (2008, forthcoming)
Vol. VI: Kraepelin in Munich, Teil I: 1903-1914 (2006), ISBN 3-933510-95-3
Vol. V: Kraepelin in Heidelberg, 1891-1903 (2005), ISBN 3-933510-94-5
Vol. IV: Kraepelin in Dorpat, 1886-1891 (2003), ISBN 3-933510-93-7
Vol. III: Briefe I, 1868-1886 (2002), ISBN 3-933510-92-9
Vol. II: Kriminologische und forensische Schriften: Werke und Briefe (2001), ISBN 3-933510-91-0
Vol. I: Persönliches, Selbstzeugnisse (2000), ISBN 3-933510-90-2