Neuropsychopharmacology: The Interface Between Genes and Psychiatric Nosology
By Thomas A. Ban
7. Psychiatric Nosology
To provide orientation points about what nosology could offer, and about the nosologies which might be suitable for use in genetic research, the history of psychiatric nosology with special reference to some of the influential classifications in psychiatry are reviewed.
7.1 Boissier de Sauvages
The origin of psychiatric nosology is in the work of Boissier de Sauvages (1768) who classified diseases, including "mania" (insanity), as if they were "specimens of natural history" by dividing them into 244 "species," 295 "genera" and 10 "classes" (Garrison 1929). His assertion that naturally occurring categories of disease can be identified in a manner which would allow the attribution of each patient to only one class by grouping the symptoms at a particular point (cross-section) in time, opened the path for the syndromic classifications of mental illness (Ban 2000b).
7.2 Philippe Pinel
The first clinically employed psychiatric nosology was Pinel's (1799, 1801). It was an empirical, "phenetic" classification, based on "meticulous description of the appearance of objects," in which "mental derangements" were "distributed" into five distinct "species" (syndromes): "melancholia (depression) or delirium (delusions) upon one subject exclusively," "mania (insanity) without delirium," "mania with delirium," "dementia or the abolition of the thinking faculty" and "idiotism or obliteration of the intellectual faculties." Pinel's (1801) classification was modified and further elaborated by Esquirol (1838).
7.3 Jean-etienne Dominique Esquirol
Esquirol (1838) divided insanity into five "general forms": "lypemany, or melancholy of the ancient," "monomania," "mania," "dementia" and "imbecility or idiocy." In variance with Pinel (1801), he assigned "melancholia" a distinct status, separated "partial insanity" ("monomania") from "insanity proper" ("mania") and distinguished within "partial insanity" three distinct forms, i.e., "intellectual," "affective" and "instinctive." Esquirol's (1838) distinction between "partial insanity" and "insanity proper" was adopted by Kahlbaum (1863).
7.4 Karl Kahlbaum
Kahlbaum (1863) classified mental illness into five categories: "vesanias," corresponding with "insanity proper," in which the syndromic expression of the disease changes through different developmental stages until it reaches dementia; "vecordias," corresponding with "partial insanity," (e.g., "paranoia", "dysthymia"), in which the syndromic expression remains essentially unchanged and restricted to one mental faculty during life time; "dysphrenias, " or symptomatic diseases linked to somatic illness; "neophrenias," which are inborn or have an onset shortly after birth; and "paraphrenias," with an onset at periods of transition in biological development, e.g., puberty, involution. Kahlbaum's (1874) postulation of a close correspondence between etiology, brain pathology, symptom pattern and outcome picture had a major impact on nosologic development in psychiatry. It Stimulated Kraepelin (1893) to adopt "Sydenham's disease model" and shift emphasis in his classification of mental illness from cross-sectional syndromes to progression of clinical manifestations (Ban 2000b).
7.5 Emil Kraepelin
Kraepelin's (1883, 1886, 1889) syndromic classification, presented in the first three editions of his textbook was gradually replaced by his disease-oriented classification. To achieve his objective, Kraepelin (1893), in the fourth edition of his text brings together three distinct syndromes, i.e., "demence precoce" (Morel 1860), "catatonia" (Kahlbaum 1874) and "dementia paranoides"(Kraepelin 1893), under the heading of "psychic degeneration processes; " and subsumes all psychiatric disorders in the 5th edition (Kraepelin 1896) under two inferential classes: "acquired" and "constitutional." In the 6th edition (Kraepelin 1899) the unifying diagnostic concept of "dementia praecox," for "hebephrenia (Hecker 1871), "catatonia" and "dementia paranoides" and the all-embracing diagnostic concept of "manic-depressive insanity" appear. All the distinct mental syndromes are pooled together and assigned on the basis of their course and outcome to one of these two categories of disease. By the time of the 7th edition (Kraepelin 1903-1904), the inferential classes of "acquired" and "constitutional" psychiatric disorders are replaced by 15 disease categories, including "manic-depressive insanity" and "dementia praecox." Seven of the remaining 13 disease categories are based on inferences or guesses about their possible causes ("exhaustion psychoses," "involutional psychoses," "paranoia," "psychogenic neuroses," "constitutional psychopathic states," "psychopathic personalities" and "defective mental development"), and six are attributed to organic, including toxic etiologies ("infection psychoses," "intoxication psychoses," "thyrogenous psychoses," "dementia paralytica," "organic dementias" and "epileptic insanity"). In the 8th edition (Kraepelin 1908-1915) the already broad diagnostic concepts are expanded. "Manic-depressive insanity" incorporates "involutional melancholia" (Dreyfus 1905) and "all cases of affective excess" and "dementia praecox" incorporates Magnan's (1893) diagnostic concept of "delire chronique" (Kraepelin 1919, 1921; Pichot 1983). However, in the same, edition, Kraepelin (1908-1915), distinguishes between the "paranoid form of dementia praecox" and the "paraphrenias." By the time Bleuler (1911) coins the term "schizophrenia," to replace the term "dementia praecox, " Kraepelin (1919) recognizes 10 different forms of "dementia praecox, i.e., "dementia simplex" (Diem 1903), "silly deterioration," (replacing the term "hebephrenia"), "depressive deterioration," "depressive deterioration with delusional formation, " "Terreular" "agitated," "periodic," "catatonic," and "paranoid" forms, and "schizophasia," and nine different end-states of the disease, i.e., "cure", "cure with defect," "simple deterioration," "imbecility with confusion of speech," "hallucinatory deterioration," "hallucinatory insanity, " "dementia paranoides," "flighty, silly deterioration" and "dull, apathetic dementia" (Fish 1962; Hamilton 1976).
7.6 Eugen Bleuler
Kraepelin's (1903-1904) classification was adopted by Eugen Bleuler (1916) with some minor modifications. By replacing the term "dementia praecox" with the term "schizophrenia," and redefining schizophrenia as a "group of psychoses" characterized "by a specific type of thinking, feeling and relation to the eternal world" which "appear in no other disease in this particular fashion," Bleuler (1911) consolidated the diagnostic concept. His "fundamental" or "basic symptoms" remained well over 50 years the most extensively employed diagnostic criteria of schizophrenia.
7.7 Carl Wernicke
Wernicke's (1899) "classification of psychoses" appeared in the same year as the 6th edition of Kraepelin's (1899) textbook. It was based on contemporary scientific contributions which were to become the structural foundation of neuroscience, e.g., the description of "multipolar cells" in the cerebral cortex (Golgi 1883), the recognition that the "neuron" is the morphological and functional unit of the nervous system (Ramon y Cajal 1897-1904) and the demonstration that the "synapse" is the functional site of transmission from one "neuron" to another (Sherrington 1896-1897, 1906). By adopting Sechenov's (1866) extension of the concept of the "reflex" as the elementary unit of mental pathology, Wernicke (1900) perceived the different forms of mental illness as "loosing of detachment from the rigid structure of associations," displayed in "hyperfunctioning, "hypofunctioning" or "parafunctioning" in the "psychosensory, " "intrapsychic," or "psychomotor" component(s) of the "psychic reflex" (Franzek 1990). Wernicke (1899) was also first to describe "motility psychosis" and "anxiety-happiness psychosis": to separate memory impairment ("dysmnesia") from personality deterioration ("dementia"); and to divide consciousness into "consciousness of the body" ("somatopsyche"), "consciousness of one's personality" ("autopsyche") and "consciousness of the external world" ("allopsyche").
7.8 Karl Kleist
Wernicke's (1900) contributions were further elaborated by Kleist (1921, 1923), who split the diagnostic concept of "schizophrenia" into two groups of diseases, “typical schizophrenias," which are confined to one neurological system, and "atypical schizophrenias, " which affect many different neurological systems in the central nervous system. Kleist (1928) was first to recognize "cycloid psychoses" as a distinct nosological category which includes Wernicke's (1900) diagnostic concepts of "anxiety psychosis" and "motility psychosis," and his own diagnostic concept of "confusion psychosis."
7.9 Karl Leonhard
Leonhard (1957) replaced Kleist's dichotomy (1928) of "typical" and "atypical schizophrenias," with the "polarity" based dichotomy of "systematic" and "unsystematic schizophrenias”; adopted Kleist's (1928) diagnostic concept of "cycloid psychoses "and Neele's (1949) diagnostic concept of "phasic psychoses”; and classified "endogenous psychoses" into five classes of illness, i.e., "unipolar phasic psychoses," "bipolar manic-depressive disease,” “bipolar cycloid psychoses," "bipolar unsystematic schizophrenias" and "unipolar systematic schizophrenias." Furthermore, on the basis of the primarily affected component of the "psychic reflex," i.e., "afferent" (sensory-perceptual- cognitive), “central -intrapsychic" (affective) or "efferent" (motor), he separated three groups of illnesses within the "systematic schizophrenias" ("paraphrenias," "hebephrenias" and catatonias), the "unsystematic schizophrenias" ("cataphasia" "affect-laden paraphrenia" and "periodic catatonia"), and the "cycloid psychoses ("confusion psychosis," "anxiety-happiness psychosis" and "motility psychosis"). He also separated "pure mania" and "pure melancholia," diseases in which the "mental pathology" extends to all three components of the "psychic reflex," from the pure "euphorias" and "pure depressions," in which the "mental pathology" is less pervasive. In Leonhard's (1936, 1961, 1986)) "differentiated nosology" there are 16 "psychopathology" based syndromes differentiated within the "systematic schizophrenias"; five "psychopathology" based syndromes within each, the "pure euphorias" and the "pure depressions" and three psychopathology based syndromes within each, the "unsystematic schizophrenias" and the "cycloid psychoses."
7.10 Kurt Schneider
Kurt Schneider's (1959) rudimentary classification was based on Karl Jaspers’ (1910, 1913, 1962) recognition that mental illness is expressed in the "form", i.e., the "mode" in which the experience appears, (e.g., "sudden primordial delusional idea," " put in the mind by hallucinatory voices"), and not in the "content" (e.g., "being persecuted") of the experience. About two decades prior to Schneider (1950), a group of German psychiatrists at the "Heidelberg Clinic" began with the re-evaluation of psychiatric nosology with the employment of Jaspers' (1913) conceptual framework. Their activity ended in 1933 with the removal of Wilmans, the head of the "Clinic," by the Nazi regime. (Gruhle, who was the intellectual leader of the group, left the university and took a position at a provincial psychiatric hospital, Mayer-Gross moved to England, etc.). What was left behind was put together by Schneider (1959) into a rudimentary classification in which "developmental anomalies," i.e., "abnormal variations of mental life," are separated from the "effects of illness and defective structure." Included among the "developmental anomalies" are "abnormal intellectual endowment," "abnormal personality" and "abnormal psychic reaction"; and included among the "effects of illness" are the "somatically based psychoses," "schizophrenia" and "cyclothymia,” the term Schneider (1959) used for "manic-depressive disease." Although Schneider (1950) retained the diagnosis of schizophrenia, he maintained that "there is nothing to which one can point as a common element in all the clinical pictures that are today christened as schizophrenia."