Review article
Neuropsychopharmacology and the genetics of schizophrenia
A history of the diagnosis of schizophrenia
Thomas A. Ban
Department of Psychiatry, Vanderbilt University, Nashville, TN, USA
Accepted 10 May 2004 - Available online 25 July 2004
2. Nosology
Development of the diagnostic concept of dementia praecox began with Kraepelin's (1893) adoption of Morel's (1857) theory of degeneration by including, in the fourth edition of his textbook, psychic degeneration processes as a distinct class of illness. The new category was characterized by rapid development of mental weakness, and included: dementia praecox — a term, Kraepelin (1893) adopted from Morel (1852, 1860) for the corresponding population to Hecker's (1871) hebephrenia —Kahlbaum's (1874) diagnostic concept of catatonia — first listed in the third edition of Kraepelin’s (1889) textbook in the class of delusional disorders — and dementia paranoids, a form of illness he separated from Kahlbaum’s (1863) diagnostic concept of paranoia.
Development of the diagnostic concept of dementia praecox continued in the fifth edition of Kraepelin’s (1896) textbook with the reassignment of the three syndromes — dementia praecox, catatonia and dementia paranoides — to the class of metabolic disease, and culminated in the sixth edition of Kraepelin’s (1899) textbook by the conceptualization of a new nosologic entity, dementia praecox, displayed in three forms: hebephrenic (Hecker, 1871), catatonic and paranoid. Instrumental to this development was Kraepelin’s (1896) overall shift in emphasis in classifying illness in the fifth edition of his textbook from clinical syndromes to progression of disease, assumedly on the influence of Kahlbaum (1863). It was also in the sixth edition that manic depressive insanity was conceptualized as a nosologic entity and separated from dementia praecox. The sixth edition Kraepelin’s (1899) textbook had worldwide success with a major impact on further classifications of mental illness.
Kraepelin’s (1899) diagnostic concept of dementia praecox was expanded with the inclusion of Magnan and Legrain’s (1895) diagnostic concept of délire chronique. By the time of the seventh edition of Kraepelin’s (1904) textbook, it embraced all disorders with a course leading to psychic invalidism of varying severity. Subsequently, however he separated paranoid deterioration (paraphrenias with prevalent delusions but without emotional and volitional psychopathology from the paranoid form of dementia praecox. Then, he identified 10 different forms of dementia praecox: dementia simplex (Diem, 1903), silly deterioration (replacing the term, hebephrenia), depressive deterioration, depressive deterioration with delusional manifestations, circular, agitated, periodic, catatonic, paranoid and schizophasia. Finally, in the eighth edition of his textbook, Kraepelin (1913) described nine different end-states of the disease: cure, cure with defect, simple deterioration imbecility with confusion of speech, hallucinatory deterioration, flighty, silly deterioration and dull, apathetic dementia. In the same edition, he defined dementia praecox as a series of clinical states which have as their common characteristic a peculiar destruction of the internal connections of the psychic personality with the most marked damage of the emotional and volitional life (Fish, 1962; Hamilton, 1976).
By the time the eight edition of Kraepelin’s (1913) textbook was published, Bleuer (1908,1911) had replaced the term dementia praecox with schizophrenia; defined schizophrenia as a group of psychosis characterized by a specific type of alteration of thinking, feeling and relation to the external world; and consolidated the diagnostic concept. His fundamental, or basic symptoms, the four A’s, i.e., loosening of associations, inappropriate affect, ambivalence and autism, were to become the most extensively employed diagnostic criteria of schizophrenia until replaced by Kurt Schneider’s (1957) first-rank symptoms (FRS): audible thoughts, voices arguing, and/or discussing, voices commenting, somatic passivity experiences, thought withdrawal and other experiences of influenced thought, thought broadcasting, delusional perceptions, other experiences involving made volition, made affect and made impulse. In spite of the extensive use of Schneider’s (1957) FRS in the diagnosis of schizophrenia, Mellor (1982) found that FRS are not exclusive for schizophrenia.
Since the time of its inception, the diagnostic concept of dementia praecox has been challenged. Wernicke (1900) argued that syndromes so far apart in clinical manifestations as the paranoid, hebephrenic and catatonic cannot be attributed to the same brain mechanisms (Healy, 2002). Kleist (1923, 1960) split schizophrenia into two classes of disease: typical schizophrenias, i.e., disease presumably confined to one neurological system and atypical schizophrenias, i.e., disease which presumably affect many different neurological systems. He also divided schizophrenia into four categories of illness, i.e., paranoid, catatonic, confused and hebephrenic and identified seven typical and one atypical forms of disease within the paranoid and the catatonic, three typical and two atypical forms of disease within the confused, and four typical forms of disease within the hebephrenic. Leonhard (1935, 1957) replaced Kleist’s (1923) dichotomy of typical schizophrenias versus atypical schizophrenias with the dichotomy of systematic schizophrenias versus unsystematic schizophrenias. He characterized systematic schizophrenias by insidious onset, process-like course and marked to moderate defect with a distinct psychopathology syndrome (end-state) in each form and subform; and distinguished unsystematic schizophrenias, by rapid onset, episodic course and mild defect with mixed psychopathologic symptoms between episodes. Leonhard (1957) also identified three forms of disease within the unsystematic schizophrenias, i.e., cataphasia, affect-laden paraphrenia and periodic catatonia, and three forms of disease with 16 sub forms within the systematic schizophrenias, i.e., six paraphrenias, four hebephrenias and six catatonias.
The contributions of Kleist (1923, 1960) and Leonhard (1936, 1957) have not been incorporated in the two major consensus-based classifications in use today. In the 10th edition of the International Classification of Disease (ICD-10) of the World Health Organization (1992) and the 4th of the American Psychiatric Association (1994), schizophrenia remains one diagnosis. In the ICD-10, the emphasis in diagnostic criteria is on Schneider’s (1957) FRS, whereas in the DSM-IV the emphasis is on the presence of delusions, hallucinations, disorganized speech and behavior, and negative symptoms, such as alogia, avolition, and affective flattening (Andreasen, 1983). One can fulfill DSM-IV criteria of schizophrenia without qualifying for either Bleuler’s (1911) or Schneider’s (1957) criteria.