tirsdag, 07-12-2021

Thomas A. Ban: In Historical Perspective: Peralta, Cuesta and their associate findings on the highest familiality of Leonhard’s classification in polynosologic study

 

Victor Peralta’s answer to Thomas A. Ban’s question

 

            In view of the higher validity of Leonhard’s system in defining more homogeneous groups of schizophrenia in terms of familial aggregation and response to treatment, Thomas Ban poses the appropriate question about if the time has come to implement Leonhard’s nosology in the current classification systems.  My own view about this question is rather pessimistic and there are several reasons for it, although I’ll discuss two, namely some limitations of Leonhard’s nosological system and the influence of the DSM classification.

            Despite the undeniable psychopathological, clinical and research value of Leonhard’s nosology, it is not without some problems. This classification is very complex, lacks operational definitions for types of disorders and it is old fashioned in several ways. For example, several symptom denominations, particularly the motor and behavioral ones, are somewhat idiosyncratic and need reformulation into more modern and recognizable terms. In this regard, the educational program of the INHN headed by Carlos Morra and Ernst Franzek is a good example of this endeavour. The classification of psychosis subtypes is rather rigid, particularly for the lower-order ones, thus leaving no room for the relatively frequent mixed or unspecified forms. Leonhard’s statement that type and subtype diagnoses can be made on the basis of the cross-sectional phenomenology (this despite he considered the course of the disorder a cornerstone in classification) is no longer tenable. For instance, it has been shown that a substantial minority of cases of cycloid psychoses, despite presenting with the typical cycloid symptoms, gradually develop residual symptomatology of several degrees (Peralta and Cuesta, 2005). Therefore, the question arises as to whether these patients should be classified as cycloid psychoses (on the basis of their typical symptoms) or unsystematic schizophrenias (on the basis of their residual states).

            A perfect fit between typical or prototypical symptoms/syndromes and specific outcomes does not exist in psychotic disorders nor in other psychiatric disorders. Together with the cross-sectional assessment of psychopathology, for an accurate diagnosis it is absolutely necessary to take into account the course of the disorder. Then the question arises about the illness duration necessary to make the diagnosis. Is it the DSM six-month criterion, the one-year criterion for defining enduring symptoms, or the informal two-year criterion for defining chronicity? Follow-up studies of first-episode samples converge to indicate an overall fair diagnostic stability of psychotic disorders during the first years of the evolution of the psychotic illness (Hesling et al., 2015), and considering the relatively high number of non-schizophrenia cases moving to a diagnosis of schizophrenia over the years, a cautionary note on the diagnosis of psychoses subtypes should be taken into account during the first years of the illness. As a personal opinion, an illness duration of at least five years is the minimum necessary to achieve an accurate diagnosis (i.e., 90% of sensitivity and specificity) of psychotic disorder subtype, this irrespective of the classification system considered. To the best of my knowledge, Leonhard never specified the follow-up time necessary for making reliable or stable diagnoses of psychotic disorders.   

            The complexity of Leonhard’s nosology together with the lack of a clear leadership of this school of thought after Helmut Beckman (Leonhard and Beckmann, 1999), among other factors, probably underlies its limited international success in terms of diffusion and validation studies. In this sense, it is frustrating to see, for example, how a recent study on the historical roots of the concept of schizophrenia (Kendler, 2016) ignores the contribution of the Wernicke-Kleist-Leonhard school.

            Regarding the DSM, its enormous impact in America and over the world has had a disastrous influence in how phenomenology and classification of psychotic disorders are viewed by mental health academicians, practising psychiatrists and researchers. This has lead Nancy Andreasen (2007) to announce the death of phenomenology in America and, I would add, over the world. She proposed “to make a serious investment in training a new generation of real experts in the science and art of psychopathology” (something with which I fully agree) and stated that “Europeans still have a proud tradition of clinical research and descriptive psychopathology” so that they “can save American science by helping us to figure out who really has schizophrenia or what schizophrenia is.” I disagree with that expectation since European psychiatry, with a few exceptions, has been corrupted by the DSM approach to psychopathology similar to levels in America. It is disappointment to see so many studies conducted over the world (and in Europe) where the clinical assessment of psychotic disorders are conducted by “trained raters” without true clinical expertise who apply structured interviews biased to rate predominantly psychotic experiences, and where sometimes the interviews are conducted telephonically!  As mentioned by Andreasen, too much investment in modern technologies (i.e., neuroimaging, genetics), when accompanied by poor phenomenological and nosological accuracy, inevitably lead to the fruitless enterprise of disentangling the etiopathology of psychotic disorders.  

            Some attempts have been made to (make) render the use of Leonhard’s classification simpler by developing diagnostic decision trees with operationalized diagnostic criteria (simply and/or operational) (Guy, 1979; Pethö and Ban, 1988; Fritze and Lanzik, 1990) (all of them) with limited success in terms of further use (or) WITHOUT validation studies. A broad implementation of Leonhard’s nosology represents an enormous venture requiring three successive steps: 1) a truly international involvement of clinicians with expertise on Leonhard’s psychopathology and nosology; 2) a modernization of this nosology in terms of simplification of the diagnostic scheme and operationalization of symptoms, other diagnostic features and diagnostic rules; and c) research strategies aimed at validating this nosology. Unfortunately, these are issues that I do not actually envision.      

 

References

 

Andreasen NC. DSM and the death of phenomenology in America: an example of unintended consequences. Schizophr Bull 2007;33:108-112.  

Fritze J, Lanzik M. Schedule for operationalized diagnosis according to the Leonhard classification of endogenous psychoses. Psychopathology, 1990;23:303-315.                 

Guy W. Manual for the classification of endogenous psychoses. 1979. International Network for the History of Neuropsychopharmacology, 2014.

Hesling M. Diagnostic change 10 years after a first episode of psychosis. Psychol Med 2015;45:2257-2769.

Kendler KS. Phenomenology of Schizophrenia and the Representativeness of Modern Diagnostic Criteria. JAMA Psychiatry. 2016;73(10):1082-1092.

Leonhard K, Beckmann H. The classification of endogenous psychoses and their differential etiology. Second, revised and enlarged edition, Springer; 1999.

Pethö B, Ban TA. DCR Budapest-Nashville in the diagnosis and classification of functional psychoses. Psychopathology. 1988;21(4-5):149-240.

Peralta V, Cuesta MJ. Cycloid Psychosis. International Review of Psychiatry, 2005; 17:53–62.

 

Victor Peralta

April 27, 2017