Unitary psychosis (Einheitspsychose) refers to the
Guislain's thesis was taken up by the German psychiatrist
For a period of two years from 1840 Wilhelm Griesinger (1817–1868) worked as a medical assistant to Zeller at the Winnental Asylum.[5] While there, he adopted and adapted his senior colleague's model of a unitary psychosis.[5] He did not, however, shares Zeller's conviction regarding the nature of the human soul or character and its role in madness.[12] A convinced somaticist and commonly considered one of the founders of materialist psychiatry,[16] in the 1845 text which established him as one of the leading scientific psychiatrists of his era, Pathologie und Therapie der psychischen Krankheiten, he conceived of character, or "psychological tonus", as derived from the action of a postulated "psychic reflex action" (psychische Reflexaktion) produced by the stimulus of the accumulated representations (Vorstellungen) of the individual's life experience.[17] The concept of psychic reflex action was drawn by analogy from the physiological reflex action of the nervous system in response to a stimulus and he argued that both forms of reflex had the same mode of action and obeyed the same physical laws.[9] Mental illnesses occurred, he posited, when the system of psychic reflex action failed to function correctly and were either diminished, leading to melancholia, or accelerated, leading to mania.[9] His belief was that mental illness was a disease of the brain but that this in turn was caused by psychological factors.[18] His emphasis on the brain as the central site of mental illness has led to his association with the so-called Somatiker (somaticists) who had argued that the causes of mental illness were entirely physical whereas their opponents, the Psychiker, insisted that mental disorders were the result of psychological perversions, moral failings, or diseases of the soul (Seelenkrankheit).[19] As with Zeller, he postulated that melancholia constituted the primary form of mental illness which then passed to mania before terminating in dementia.[20] In his 1861 text Mental Pathology and Therapeutics Griesinger proposed a classificatory division of types of mental anomalies between those characterised by emotional disturbances and those characterised by disturbances in the intellectual and volitional functions.[1] He argued, based on his observation of cases, that the former condition preceded the latter where disorders of the intellect and will appeared "only as consequences and terminations" of disturbances of the emotions if "the cerebral affliction has not been cured".[21] These two categories thus constituted, for Griesigner, "the different forms [and] the different stages of one morbid process".[22] The general trajectory of this mental pathology tended towards "a constant progressive course, which may even proceed to complete destruction of the mental life".[23] Greisinger maintained his belief in unitary psychosis until the 1860s.[12]
The greatest defender and the most radical proponent of the concept of unitary psychosis in the 19th century was the German
From the 1860s the concept of unitary psychosis and its advocates came under increasing criticism. Karl Ludwig Kahlbaum (1829–1899), a German psychiatrist of seminal importance in the development of the modern nosology and a formative influence on the work of Emil Kraepelin,[32] had taken issue with Neumann's assertion in his 1859 text that mental illness could not be categorised into discrete disease entities.[33] Kahlbaum fashioned a response in 1863 with the publication of his Die Gruppierung der psychischen Krankheiten (The Classification of Psychiatric Diseases).[34] This text delineated four distinct types of mental illness (vesania): vesania acuta, vesania typica, vesania progressiva and vesania catatonica.[32] He asserted that the unitarian position signalled the "end to all diagnosis in the field of psychopathology."[35] For Kahlbaum, Neumann's failure to engage in any attempt at disease classification, his rejection of diagnosis as abstraction and his focus only upon the individual manifestation of mental illness constituted an enterprise without any scientific validity.[36] In the absence of meaningful and acute diagnostic categories in psychiatry Kahlbaum believed that both the development of effective therapeutic practices and the knowledge of mental illness would run stagnant.[36]
During his inaugural lecture following his appointment to the chair of psychiatry in Dorpat University in 1887, Kraepelin contended that Zeller's notion of unitary psychosis had led to the calcification of clinical research in Germany until as late as the 1860s. The revival of a more objective clinical approach built upon observation, he contended, had had to await the contribution of researchers such as Ludwig Snell who wrote on monomania as a distinct disease entity in the 1870s.[37] Kraepelin's approach to classification of mental illness was based on longitudinal studies of symptoms, course and outcome. He concluded from his studies that there were only two major forms of serious mental illness: dementia praecox and manic depression. This division of the psychoses, currently enshrined in modern classification systems as that between schizophrenia and bipolar disorder and referred to as the Kraepelinian dichotomy, has remained in place for more than a hundred years.[38]
Variations of the unitary psychosis thesis have been revived occasionally during the 20th century. These have generally taken the form of statistical analyses that purport to demonstrate that the Kraeplinian division is unstable.[39] In the modern era the concept of schizoaffective psychosis, which straddles the Kraepelinian divide, when delineated as a condition sharing a common causal pathway as both schizophrenia and affective psychosis, shares aspects of the more radical notion of unitary psychosis in regarding the individual psychoses as points on a continuum.[40]