Diagnostic concordance in functional psychosis revisited: a study of inter-relationships between alternative concepts of psychotic disorder

Familiality of Psychotic Disorders: A Polynosologic Study in Multiplex Families

INTRODUCTION

Phenotype definition of psychotic disorders has a strong impact on the degree of familial aggregation. Nevertheless, the extent to which distinct classification systems affect familial aggregation (ie, familiality) remains an open question. This study was aimed at examining the familiality associated with 4 nosologic systems of psychotic disorders (DSM-IV, ICD-10, Leonhard's classification and a data-driven approach) and their constituting diagnoses in a sample of multiplex families with psychotic disorders.

METHODS

Participants were probands with a psychotic disorder, their parents and at least one first-degree relative with a psychotic disorder. The sample was made of 441 families comprising 2703 individuals, of whom 1094 were affected and 1709 unaffected.

RESULTS

The Leonhard classification system had the highest familiality (h (2) = 0.64), followed by the empirical (h (2) = 0.55), DSM-IV (h (2) = 0.50), and ICD-10 (h (2) = 0.48). Familiality estimates for individual diagnoses varied considerably (h (2) = 0.25-0.79). Regarding schizophrenia diagnoses, Leonhard's systematic schizophrenia (h (2) = 0.78) had the highest familiality, followed by latent class core schizophrenia (h (2) = 0.74), DSM-IV schizophrenia (h (2) = 0.48), and ICD-10 schizophrenia (h (2) = 0.41). Psychotic mood disorders showed substantial familiality across nosologic systems (h (2) = 0.60-0.77). Domains of psychopathology other than reality-distortion symptoms showed moderate familiality irrespective of diagnosis (h (2) = 0.22-0.52) with the deficit syndrome of schizophrenia showing the highest familiality (h (2) = 0.66).

CONCLUSIONS

While affective psychoses showed relatively high familiality estimates across classification schemes, those of nonaffective psychoses varied markedly as a function of the diagnostic scheme with a narrow schizophrenia phenotype maximizing its familial aggregation. Leonhard's classification of psychotic disorders may be better suited for molecular genetic studies than the official diagnostic systems.

Cycloid psychoses revisited: case reports, literature review, and commentary

Emil Kraepelin proposed to separate psychiatric disorders with psychotic features into two major categories, dementia praecox (later schizophrenia) and manic-depressive insanity (later bipolar disorder and major depression). Over the past century, there have been many efforts to categorize conditions that do not fit readily in either group. These conditions include many cases of acute psychotic illnesses of limited duration, with recovery between recurrences. For some of these conditions, Karl Kleist proposed the term cycloid psychosis: acute features were psychotic, as in schizophrenia, but the course was episodic, as in manic-depression. His concept was later elaborated by Karl Leonhard and Carlo Perris, and validated by modern studies. Leonhard described three overlapping cycloid subtypes (anxiety-beatific, excited-inhibited confusional, and hyperkinetic-akinetic motility dysfunction forms); Perris proposed a more unitary syndrome with operational diagnostic criteria; and recent investigators have considered relatively affective versus thought-disordered subtypes. The cycloid concept is not explicitly included in standard international diagnostic schemes, but both DSM-IV and ICD-10 have broad categories for acute, recurrent psychotic disorders, whose validity remains insecure. We present two cases of probable cycloid psychosis, review the history of the concept, and propose that it be reconsidered as a clinically useful category whose validity and utility for prognosis and treatment can be further tested.

Competing definitions of schizophrenia: what can be learned from polydiagnostic studies?

The contemporary diagnoses of schizophrenia (sz)-Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition(DSM-IV) and International Classification of Diseases, 10th Revision(ICD-10)-are widely considered as important scientific achievements. However, these algorithms were not a product of explicit conceptual analyses and empirical studies but defined through consensus with the purpose of improving reliability. The validity status of current definitions and of their predecessors remains unclear. The so-called "polydiagnostic approach" applies different definitions of a disorder to the same patient sample in order to compare these definitions on potential validity indicators. We reviewed 92 polydiagnostic sz studies published since the early 1970s. Different sz definitions show a considerable variation concerning frequency, concordance, reliability, outcome, and other validity measures. The DSM-IV and the ICD-10 show moderate reliability but both definitions appear weak in terms of concurrent validity, eg, with respect to an aggregation of a priori important features. The first-rank symptoms of Schneider are not associated with family history of sz or with prediction of poor outcome. The introduction of long duration criteria and exclusion of affective syndromes tend to restrict the diagnosis to chronic stable patients. Patients fulfilling the majority of definitions (core sz patients) do not seem to constitute a strongly valid subgroup but rather a severely ill subgroup. Paradoxically, it seems that a century after the introduction of the sz concept, research is still badly needed, concerning conceptual and construct validity of sz, its essential psychopathological features, and phenotypic boundaries.

Cycloid psychosis: an examination of the validity of the concept

The diagnosis of cycloid psychosis has a long tradition in European psychiatry. However, it has been poorly assimilated within the DSM IV and ICD-10 diagnostic systems. Leonhard set the basis for the current conceptualization of the disorder, and Perris and Brockington developed the first operational diagnostic criteria. However, the two conceptualizations of the disorder are not the same and differ across a number of meaningful variables. Cycloid psychosis is a useful concept in that it possesses both clinical and predictive validity. Despite the high prevalence of mood symptoms and syndromes, cycloid psychosis does not equal schizoaffective disorder. Although a substantial body of evidence suggests that cycloid psychosis differs meaningfully from typical schizophrenia, it is less clear whether it differs from major mood disorders or represents an independent nosological entity. The existence of putative subtypes is also likely, and the differentiation between affective and nonaffective subtypes has received some support.

Diagnostic significance of Schneider's first-rank symptoms in schizophrenia. Comparative study between schizophrenic and non-schizophrenic psychotic disorders

BACKGROUND

Despite the lack of consistent empirical support, modern diagnostic criteria of schizophrenia give particular emphasis to Schneider's first-rank symptoms (FRSs).

AIMS

To examine the diagnostic significance of FRSs for schizophrenia by trying to overcome the limitations of previous studies.

METHODS

This study examined the diagnostic accuracy of FRSs for schizophrenia in 660 in-patients with the full spectrum of functional psychotic disorders. Schizophrenia was diagnosed according to three criteria: DSM-III-R broad, DSM-III-R narrow and Feighner, the latter being considered as the gold standard because it does not give particular emphasis of FRSs.

RESULTS

FRSs were highly prevalent in both schizophrenia and non-schizophrenic psychoses. The likelihood ratios (and 95% CI) of one or more FRSs for Feighner, DSM-III-R narrow and DSM-III-R broad schizophrenia were 1.06 (0.94-1.20), 1.23 (1.09-1.39) and 1.73 (1.44-2.08), respectively. These data indicate that FRSs do not significantly increase the likelihood of having schizophrenia.

CONCLUSIONS

FRSs are not useful in differentiating schizophrenia from other psychotic disorders. Diagnostic systems for schizophrenia that are heavily based on these symptoms may arise from a tautological definition of the disorder.

The dimensionality of schizophrenia concepts in first-episode psychosis

This study aimed to determine the dimensionality of concepts of schizophrenia using 11 different diagnostic systems, and then to identify the nature of these dimensions by their relationship to a range of signs and symptoms. The sample consisted of 479 patients admitted with a first episode of functional psychosis. The underlying structure of the 11 diagnostic systems was best represented by an oblique 3-factor solution. Whereas the second and third factors could be meaningfully interpreted by their correlations with signs and symptoms, the first factor, anchored by 'modern' nosologies such as DSM-III-R, was more clearly specified by what it is not (the absence of affective symptoms) rather than by what it is (the presence of characteristic psychotic symptoms). A logistic regression of DSM-III-R diagnosis on to separate diagnostic components supports the contention that duration of illness and affective exclusion criteria discriminate the presence of DSM-III-R schizophrenia much better than the three characteristic psychotic symptom groupings.

Early intervention in schizophrenia

The management of schizophrenia may be characterised by two paradigms. The first approaches the schizophrenias as episodic relapsing disorders, where treatment is provided through both acute (crisis) care and to achieve prophylaxis. The second paradigm, sometimes arising from a failure of the first, is of "rehabilitation", involving amelioration of disabilities, occasionally within a framework of relative asylum. We would propose a third paradigm of "early intervention", involving a combination of medical and psychosocial interventions targeted at young, vulnerable people with the aim of preventing or limiting likely social, psychological and mental deterioration. Vigorous intervention early in the course of illness, early recognition and treatment of relapse and the promotion of psychological adjustment to psychotic illness are proposed as key elements of this third paradigm.