Would the use of dimensions instead of categories remove problems related to subthreshold disorders?

Scientific progress fostered in DSM and ICD over the past quarter of century has significantly increased awareness of the limitation of categorical definitions of mental illness. Disorders highly merge into another with no natural boundary in between. The addition of continuous, “dimensional” measures into the various diagnostic domains might help resolve some of the critical taxonomic issues currently facing the field of mental health. It was overtly recognized that both categorical and dimensional approaches to diagnosis are important both for clinical work and for research, and that the ideal taxonomy would offer both. Within each diagnostic entity, there are multiple options for creating a dimensional scale based on a categorical definition. The ICD 10 and DSM IV have no place for subthreshold disorders except in atypical, not otherwise specified or to marginalize its existence with subsequent suffering and impairment of the patients. The chapter will discuss how the subthreshold affective, psychotic, anxiety, cognitive and substance abuse and other psychiatric disorders contribute to psychiatric morbidity and impairment. The chapter discusses the impairment and suffering of patients with subthreshold various psychiatric disorders and how its inclusion in a dimensional approach may result in ameliorating the suffering of that group as their current status may initiate some ethical considerations for their management.

     

Creating a map of psychiatric patients based on psychopathological symptom profiles

Background  In the current debate about the categorical or dimensional classification of mental disorders many fruitful methods to illustrate one or the other aspect are employed, and suggestions are made to combine the two perspectives. Methods  We present such an approach to combine both perspectives at the same time. Based on psychopathological AMDP-symptom profiles, a map of psychiatric patients was calculated by robust nonmetric multidimensional scaling (NMDS). Results  The sample from the Ludwig-Maximilians University in Munich included the records of patients, who were admitted and discharged in 2002 and 2003 with a diagnosis of either paranoid schizophrenia, (F20.00, N = 24), bipolar affective disorder, current episode manic without psychotic symptoms (F31.1, N = 32) or severe depressive episode without psychotic symptoms (F32.2, N = 78). In the resulting map of patients we found a clear categorical distinction according to the diagnostic groups, but also high regression values of AMDP-syndromes (manic syndrome: r = 0.83, depressive syndrome: r = 0.68, and paranoid-hallucinatory syndrome, r = 0.62). Discussion  The map of psychiatric patients presents an approach to consider the categorical and dimensional aspects at the same time. We were able to identify meaningful delineations between diagnostic clusters as well as continuous transitions. This method allows the whole psychopathological profile of each individual patient to be considered and also to identify misdiagnosed cases at a glance.     

Reliability of DSM and empirically derived prototype diagnosis for mood,anxiety and personality disorders

BackgroundProminent psychiatric diagnostic systems such as the DSM-IV and ICD-10 have shown low reliability in clinical practice. An alternative approach to classification of psychiatric disorders is prototype matching. In the current study, we examined reliability of assessing mood, anxiety and personality disorders using a multi-method multi informant approach. More specifically, we examined diagnosis made by treating clinician and independent expert clinical interviewer, using three different diagnostic systems (DSM symptom count, DSM-IV prototype diagnosis and empirically derived prototype diagnosis).MethodsA convenience sample of clinicians (N = 80) and patients (N = 170) from eight community mental health clinics in Israel participated in the study.ResultsOur findings show fair to excellent interrater reliability for prototype dimensional diagnostic systems (ranged from 0.40 to 0.79) for most mood and anxiety disorders examined. Overall, dimensional diagnostic systems, yielded better interrater reliability for mood, anxiety and personality disorders, as compared with categorical diagnosis. There were no significant differences between dimensional systems.ConclusionsOur findings provide further support to the advantages of dimensional over categorical models in increasing reliability.     

Kraepelin, biological psychiatry, and beyond

One of Kraepelin's major contributions has been the introduction of the nosological principle in psychiatry. Mental pathology, he presumed, is subdividable in discrete entities each based on a specific pathophysiology. Kraepelin provided the diagnostic process in psychiatry with a solid infrastructure. It has been used in biological psychiatric research until this very day. Searching for the biological determinants of categorical entities has been its major goal. The yield of those efforts has been meagre, in that none of the biological findings reported so far seemed to be specific for a particular nosological entity. The question thus arises: is nosology the right model to classify mental disorders. It is suggested that it is not. The disease categories presently delineated are utterly heterogeneous, and therefore cannot be expected to have a well-defined pathophysiology. The nosological system cannot be rejected (as yet), but it has to be upgraded by incorporation of a strong dynamic-functional component. The functional components should become the focus of biological psychiatric research. The question whether an alternative classificatory model, such as the reaction form model, has to be preferred in biological psychiatry should become a matter of serious discussion.     

The position of delusional parasitosis in psychiatric nosology and classification

Discussions on the nosological position of delusional parasitosis (DP) have resulted in a wide range of opinions. In the present study in 34 patients with DP, the various and contradictory opinions concerning DP positioning in psychiatric nosology were examined through clinical, psychopathological, and polydiagnostic analyses using VRC, DSM-III, DSM-III-R and ICD-9. The psychopathological analyses with VRC as well as the polydiagnostic comparisons with other classification systems indicated that DP is neither a nosological entity nor due to a specific psychiatric illness. As our results showed, DP is a nosologically unspecific syndrome, which may occur superimposed on all psychiatric disorders.     

Kraepelin,biological psychiatry,and beyond

One of Kraepelin’s major contributions has been the introduction of the nosological principle in psychiatry. Mental pathology, he presumed, is subdividable in discrete entities each based on a specific pathophysiology. Kraepelin provided the diagnostic process in psychiatry with a solid infrastructure. It has been used in biological psychiatric research until this very day. Searching for the biological determinants of categorical entities has been its major goal. The yield of those efforts has been meagre, in that none of the biological findings reported so far seemed to be specific for a particular nosological entity. The question thus arises: is nosology the right model to classify mental disorders. It is suggested that it is not. The disease categories presently delineated are utterly heterogeneous, and therefore cannot be expected to have a well-defined pathophysiology. The nosological system cannot be rejected (as yet), but it has to be upgraded by incorporation of a strong dynamic-functional component. The functional components should become the focus of biological psychiatric research. The question whether an alternative classificatory model, such as the reaction form model, has to be preferred in biological psychiatry should become a matter of serious discussion.

     

Die Krise der operationalen Diagnostik in der Psychiatrie

Based on historical and current contributions, the operational diagnostic approach is examined from a psychopathological point of view. Operational diagnostic systems in psychiatry are characterised by an atomising approach. In this context, psychopathological symptoms are interpreted as elementary entities which can be combined into a specific diagnostic category. Many years before operational diagnostic systems were introduced into psychiatry, however, such an atomising procedure was criticised by authors like Karl Jaspers, Willy Mayer-Gross or Klaus Conrad. Furthermore, validation of diagnostic criteria of operational diagnostic systems has not succeeded so far using biological findings or results of family and follow-up studies. This may be one reason for the fact that categorical approaches in psychiatric diagnosis are questioned increasingly and dimensional diagnostic models are suggested.     

Modifications in the psychopathologic definition of schizophrenia—Alterations during the last two decades: Expectations for the future

Since Kraepelin,¹ at the end of the last century, compounded some distinct psychiatric disorders already described by others into a nosological entity that was subsequently named “schizophrenia” by Eugen Bleuler,² discussion on the psychopathological criteria to be employed in diagnosis of this disease has not ceased. The diagnostic guidelines in practice up to the 1960s have, during the last two decades, been subjected to increased questioning, out of which new psychopathological concepts seem to be emerging.     

Dimensions and the psychosis phenotype

In this paper, we discuss the conceptual background for including a dimensional component to the DSM V diagnoses for psychoses. We review the evidence for a continuous distribution of psychosis like symptoms in the general population and summarise the research validating the clinical usefulness of psychopathological dimensions. We conclude that diagnostic models using both categorical and dimensional representations of psychosis have better predictive validity than either model independently. Dimensions do not appear to be diagnosis specific so a flexible scoring of dimensions across all psychotic and major affective disorders may be potentially more informative than a system where categorical diagnoses are kept artificially dimension-specific.     

Schizoaffective disorder–an ongoing challenge for psychiatric nosology

Objective

Schizoaffective disorder is a common diagnosis in mental health services. The present article aims to provide an overview of diagnostic reliability, symptomatology, outcome, neurobiology and treatment of schizoaffective disorder.

Method

Literature was identified by searches in “Medline” and “Cochrane Library”.

Results

The diagnosis of schizoaffective disorder has a low reliability. There are marked differences between the current diagnostic systems. With respect to psychopathological symptoms, no clear boundaries were found between schizophrenia, schizoaffective disorder and affective disorders. Common neurobiological factors were found across the traditional diagnostic categories. Schizoaffective disorder according to ICD-10 criteria, but not to DSM-IV criteria, shows a more favorable outcome than schizophrenia. With regard to treatment, only a small and heterogeneous database exists.

Conclusion

Due to the low reliability and questionable validity there is a substantial need for revision and unification of the current diagnostic concepts of schizoaffective disorder. If future diagnostic systems return to Kraepelin's dichotomous classification of non-organic psychosis or adopt a dimensional diagnostic approach, schizoaffective disorder will disappear from the psychiatric nomenclature. A nosological model with multiple diagnostic entities, however, would be compatible with retaining the diagnostic category of schizoaffective disorder.     

Boundaries of mental disorders

PURPOSE OF REVIEW: This article reviews the problem of 'boundaries' in psychopathology and its conceptualization in the diagnostic classification of psychiatric disorders. RECENT FINDINGS: A modest number of publications in 2004-2005 contribute concepts, methods and data relevant to several aspects of the problem: scientific 'facts' versus value attribution in the definition of mental disorders; the problem of comorbidity between diagnostic entities; the spurious dichotomy between categorical versus dimensional approaches to diagnosis and classification; and the distinction between validity and pragmatic utility. SUMMARY: The relative paucity of research explicitly addressing these issues should be a reason for concern in the debate leading up to the next revisions of the International Classification of Diseases and the Diagnostic and Statistical Manual of Mental Disorders.     

Psychiatric problems in patients from Arab countries

In 1979-1988 at the Prague Psychiatric Clinic 26 patients from Arab areas were hospitalized. The reason for admission were acute mental disorders involving paranoid, paranoid hallucinatory, manic or depressive syndromes, alcoholism and aggressive behaviour. No bizarre or at least remote psychopathological symptoms were recorded. The author draws attention to the frequent incidence of alcoholism and aggressiveness: these manifestations are at variance with traditions of Arab morality. In the diagnostic evaluation syndromological conclusions proved more useful than nosological ones.     

Psychiatric comorbidity in epilepsy

Many studies on psychiatric comorbidity in epilepsy have been performed using many different patient groups and diagnostic instruments. This methodological heterogeneity complicates comparison of the findings. In this article, psychiatric disorders in epilepsy are reviewed from the perspective of the DSM classification system. The empirical findings of axis I clinical disorders and axis II personality disorders are described separately. Furthermore, the existence and specificity of conditions such as interictal dysphoric disorder, interictal behavior syndrome, and psychosis of epilepsy are discussed. From the many studies that have been performed on this topic it can be learned that there is a need for well-controlled studies using representative patient groups and valid and standardized diagnostic instruments. So far, the majority of the studies have concerned axis I disorders; relatively little research has been performed on axis II personality disorders. More research on personality disorders, as well as on the relative contributions of the different (brain- and non-brain-related) factors to the relationship between epilepsy and psychiatric disorders, is recommended.     

Biochemical aspects of dysphoria: case study for hypothesis generation

Comparing the pattern of serotonin, 5-hydroxyindole acetic acid, 3,4-dihydroxyphenyl acetic acid and homovanillic acid in five brain areas of one dysphoric patient to those of 3 depressed patients it seems that dysphoria biochemically is a state between depression and mania. Dynamically, dysphoria may possibly be seen as a behavioral correlate of a switch process between high and low turnover of neurotransmitters (rather high frequency in comparison to bipolar disorder with very low frequency). However, the biochemical data are obviously in agreement with psychiatric findings, i.e. that dysphoria in any case is an extremely labile state.     

Classifying psychotic disorders: issues regarding categorial vs. dimensional approaches and time frame to assess symptoms

The study's aims were to empirically derive classes of disorders and dimensional syndromes within psychotic disorders on the basis of the three time frames of symptom assessment and to comparatively examine their external validity. The level of concordance among classes and among dimensions across the time frames was generally low. The external correlates of psychopathological syndromes differed as a function of both type of assessment and the dimensional or categorical approach used. The dimensional approach was more effective than the categorical approach in predicting a set of clinical variables, irrespective of the time frame used to assess the symptoms. It is concluded that classification of psychotic disorders is highly dependent upon the time frame considered to assess symptoms and that dimensional classifications do have higher predictive power than categorical ones. Received: 13 June 2001 / Accepted: 31 October 2001     

Psychopathological Syndromes Across Affective and Psychotic Disorders Correlate With Gray Matter Volumes

IntroductionMore than a century of research on the neurobiological underpinnings of major psychiatric disorders (major depressive disorder [MDD], bipolar disorder [BD], schizophrenia [SZ], and schizoaffective disorder [SZA]) has been unable to identify diagnostic markers. An alternative approach is to study dimensional psychopathological syndromes that cut across categorical diagnoses. The aim of the current study was to identify gray matter volume (GMV) correlates of transdiagnostic symptom dimensions. MethodsWe tested the association of 5 psychopathological factors with GMV using multiple regression models in a sample of N = 1069 patients meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for MDD (n = 818), BD (n = 132), and SZ/SZA (n = 119). T1-weighted brain images were acquired with 3-Tesla magnetic resonance imaging and preprocessed with CAT12. Interactions analyses (diagnosis × psychopathological factor) were performed to test whether local GMV associations were driven by DSM-IV diagnosis. We further tested syndrome specific regions of interest (ROIs). ResultsWhole brain analysis showed a significant negative association of the positive formal thought disorder factor with GMV in the right middle frontal gyrus, the paranoid-hallucinatory syndrome in the right fusiform, and the left middle frontal gyri. ROI analyses further showed additional negative associations, including the negative syndrome with bilateral frontal opercula, positive formal thought disorder with the left amygdala-hippocampus complex, and the paranoid-hallucinatory syndrome with the left angular gyrus. None of the GMV associations interacted with DSM-IV diagnosis. ConclusionsWe found associations between psychopathological syndromes and regional GMV independent of diagnosis. Our findings open a new avenue for neurobiological research across disorders, using syndrome-based approaches rather than categorical diagnoses.