Deconstructing psychosis

Affective symptom dimensions in early-onset psychosis over time: a principal component factor analysis of the Young Mania Rating Scale and the Hamilton Depression Rating Scale

Early-onset psychosis (EOP) is a complex disorder characterized by a wide range of symptoms, including affective symptoms. Our aim was to (1) examine the dimensional structure of affective symptoms in EOP, (2) evaluate the predominance of the clinical dimensions and (3) assess the progression of the clinical dimensions over a 2-year period. STROBE-compliant prospective principal component factor analysis of Young Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale-21 (HDRS-21) at baseline, 6-months, 1-year and 2-year follow-up. We included 108 EOP individuals (mean age = 15.5 ± 1.8 years, 68.5% male). The factor analysis produced a four-factor model including the following dimensions: mania, depression/anxiety, sleep and psychosis. It explained 47.4% of the total variance at baseline, 60.6% of the total variance at 6-months follow-up, 54.5% of the total variance at 1-year follow-up and 49.5% of the total variance at 2-year follow-up. According to the variance explained, the mania factor was predominant at baseline (17.4%), 6-month follow-up (23.5%) and 2-year follow-up (26.1%), while the depression/anxiety factor was predominant at 1-year follow-up (23.1%). The mania factor was the most stable; 58.3% items that appeared in this factor (with a load > 0.4) at any time point appeared in the same factor at ≥ 3/4 time points. Affective symptoms are frequent and persistent in EOP. Mania seems to be the most predominant and stable affective dimension. However, depression and anxiety may gain predominance with time. A comprehensive evaluation of the dimensional structure and the progression of affective symptoms may offer clinical and therapeutic advantages.

Alpha7 nicotinic-N-methyl-D-aspartate hypothesis in the treatment of schizophrenia and beyond

Development of novel treatments for positive, cognitive, and negative symptoms continue to be a high-priority area of schizophrenia research and a major unmet clinical need. Given that all randomized controlled trials (RCTs) conducted to date failed with one add-on medication/mechanism of action, future RCTs with the same approach are not warranted. Even if the field develops a medication for cognition, others are still needed to treat negative and positive symptoms. Therefore, fixing one domain does not completely solve the problem. Also, targeting the cholinergic system, glutamatergic system, and cholinergic plus alpha7 nicotinic and N-methyl-D-aspartate (NMDA) receptors failed independently. Hence, targeting other less important pathophysiological mechanisms/targets is unlikely to be successful. Meta-analyses of RCTs targeting major pathophysiological mechanisms have found some efficacy signal in schizophrenia; thus, combination treatments with different mechanisms of action may enhance the efficacy signal. The objective of this article is to highlight the importance of conducting RCTs with novel combination treatments in schizophrenia to develop antischizophrenia treatments. Positive RCTs with novel combination treatments that target the alpha7 nicotinic and NMDA receptors simultaneously may lead to a disease-modifying therapeutic armamentarium in schizophrenia. Novel combination treatments that concurrently improve the three domains of psychopathology and several prognostic and theranostic biomarkers may facilitate therapeutic discovery in schizophrenia.

Atypical processing of uncertainty in individuals at risk for psychosis

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Humans at psychosis clinical high risk (CHR) over-estimate environmental volatility.

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Low-level prediction error (PE) signals evoke increased frontal activity in CHR.

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Volatility-related PEs are associated with reduced frontal activity in CHR.

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Frontal cortical activation to low-level PEs reflects impaired clinical functioning.

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Atypical PE learning signal representations may promote delusion formation in CHR.

Current theories of psychosis highlight the role of abnormal learning signals, i.e., prediction errors (PEs) and uncertainty, in the formation of delusional beliefs. We employed computational analyses of behaviour and functional magnetic resonance imaging (fMRI) to examine whether such abnormalities are evident in clinical high risk (CHR) individuals.

Non-medicated CHR individuals (n = 13) and control participants (n = 13) performed a probabilistic learning paradigm during fMRI data acquisition. We used a hierarchical Bayesian model to infer subject-specific computations from behaviour – with a focus on PEs and uncertainty (or its inverse, precision) at different levels, including environmental ‘volatility’ – and used these computational quantities for analyses of fMRI data.

Computational modelling of CHR individuals’ behaviour indicated volatility estimates converged to significantly higher levels than in controls. Model-based fMRI demonstrated increased activity in prefrontal and insular regions of CHR individuals in response to precision-weighted low-level outcome PEs, while activations of prefrontal, orbitofrontal and anterior insula cortex by higher-level PEs (that serve to update volatility estimates) were reduced. Additionally, prefrontal cortical activity in response to outcome PEs in CHR was negatively associated with clinical measures of global functioning.

Our results suggest a multi-faceted learning abnormality in CHR individuals under conditions of environmental uncertainty, comprising higher levels of volatility estimates combined with reduced cortical activation, and abnormally high activations in prefrontal and insular areas by precision-weighted outcome PEs. This atypical representation of high- and low-level learning signals might reflect a predisposition to delusion formation.

Does reason for referral to an ultra-high risk clinic predict transition to psychosis?

AIM

To examine reasons for referral to a specialist ultra-high risk (UHR) for psychosis clinic and whether these reasons are associated with risk for subsequent transition to psychosis.

METHODS

Data for 127 patients referred to the Personal Assessment and Crisis Evaluation clinic were collected by medical record audit. Time to transition to psychosis was calculated from date of referral to time at which the young person was judged by their treating team to be experiencing onset of first episode psychosis.

RESULTS

Patients were primarily referred due to attenuated psychotic symptoms and depression (40.2%). There was an association with transition, with those in the attenuated psychotic-symptom-only category being more likely to transition.

CONCLUSION

As well as attenuated psychotic symptoms, depression and anxiety were also important reasons for referral indicating that there is a broad clinical phenotype of young people presenting to UHR clinics. Clinical reason for referral may index level of risk for subsequent transition to psychosis.

The Kraepelinian tradition

Emil Kraepelin (1856-1926) was an influential figure in the history of psychiatry as a clinical science. This paper, after briefly presenting his biography, discusses the conceptual foundations of his concept of mental illness and follows this line of thought through to late 20th-century “Neo-Kraepelinianism,” including recent criticism, particularly of the nosological dichotomy of endogenous psychoses. Throughout his professional life, Kraepelin put emphasis on establishing psychiatry as a clinical science with a strong empirical background. He preferred pragmatic attitudes and arguments, thus underestimating the philosophical presuppositions of his work. As for nosology, his central hypothesis is the existence and scientific accessibility of “natural disease entities” (“natürliche Krankheitseinheiten”) in psychiatry. Notwithstanding contemporary criticism that he commented upon, this concept stayed at the very center of Kraepelin's thinking, and therefore profoundly shaped his clinical nosology.

A dimensional comparison between delusional disorder, schizophrenia and schizoaffective disorder

INTRODUCTION

Since the early description of paranoia, the nosology of delusional disorder has always been controversial. The old idea of unitary psychosis has now gained some renewed value from the dimensional continuum model of psychotic symptoms.

AIMS

1. To study the psychopathological dimensions of the psychosis spectrum; 2. to explore the association between psychotic dimensions and categorical diagnoses; 3. to compare the different psychotic disorders from a psychopathological and functional point of view.

MATERIAL AND METHODS

This is an observational study utilizing a sample of some 550 patients with a psychotic disorder. 373 participants had a diagnosis of schizophrenia, 137 had delusional disorder and 40 with a diagnosis of schizoaffective disorder. The PANSS was used to elicit psychopathology and global functioning was ascertained using the GAF measure. Both exploratory and confirmatory factor analyses of the PANSS items were performed to extract psychopathological dimensions. Associations between diagnostic categories and dimensions were subsequently studied using ANOVA tests.

RESULTS

5 dimensions - manic, negative symptoms, depression, positive symptoms and cognitive - emerged. The model explained 57.27% of the total variance. The dimensional model was useful to explained differences and similarities between all three psychosis spectrum categories. The potential clinical usefulness of this dimensional model within and between clinical psychosis spectrum categories is discussed.

Polygenic risk scores in bipolar disorder subgroups

BACKGROUND

Bipolar disorder (BD) is a genetically and clinically heterogeneous disorder. Current classifications of BD rely on clinical presentations without any validating biomarkers, making homogenous and valid subtypes warranted. This study aims at investigating whether a BD polygenic risk score (PGRS) can validate BD subtypes including diagnostic sub-categories (BD-I versus BD-II), patients with and without psychotic symptoms, polarity of first presenting episode and age at onset based groups. We also wanted to investigate whether illness severity indicators were associated with a higher polygenic risk for BD.

METHODS

Analyze differences in BD PGRS scores between suggested subtypes of BD and between healthy controls (CTR) and BD in a sample of N=669 (255 BD and 414 CTR).

RESULTS

The BD PGRS significantly discriminates between BD and CTR (p<0.001). There were no differences in BD PGRS between groups defined by diagnostic sub-categories, presenting polarity and age at onset. Patients with psychotic BD had nominally significantly higher BD PGRS than patients with non-psychotic BD after controlling for diagnostic sub-category (p=0.019). These findings remained trend level significant after Bonferroni corrections (p=0.079).

LIMITATIONS

The low explained variance of the current PGRS method could lead to type II errors.

CONCLUSIONS

There are nominally significant differences in BD PGRS scores between patients with and without psychotic symptoms, indicating that these two forms of BD might represent distinct subtypes of BD based in its polygenic architecture and a division between BD with and without psychotic symptoms could represent a more valid subclassification of BD than current diagnostic sub-categories. If replicated, this finding could affect future research, diagnostics and clinical practice.

[A new classification for better care. The promises of the translational psychiatric neuroscience]

This article explores the way neuroscientists call for the "deconstruction" of the classifications of mental disorders as we know them, in order to provide solutions to the slowdown of therapeutical innovation in psychiatry. It is based on the case study of the Research Domain Criteria (RDoC) project of the US National Institute of Mental Health (NIMH). My purpose is to show that neuroscience interested in mental disorders offers narratives of innovation, transformation, and desirable futures that are at the heart of the ambitious current research projects and influence them. I approach the versions of the futures proposed by the promoters of translational psychiatric neuroscience in terms of productivity at the scientific, epistemological and socio-political levels.

The Kraepelinian tradition

Emil Kraepelin (1856-1926) was an influential figure in the history of psychiatry as a clinical science. This paper, after briefly presenting his biography, discusses the conceptual foundations of his concept of mental illness and follows this line of thought through to late 20th-century "Neo-Kraepelinianism," including recent criticism, particularly of the nosological dichotomy of endogenous psychoses. Throughout his professional life, Kraepelin put emphasis on establishing psychiatry as a clinical science with a strong empirical background. He preferred pragmatic attitudes and arguments, thus underestimating the philosophical presuppositions of his work. As for nosology, his central hypothesis is the existence and scientific accessibility of "natural disease entities" ("natürliche Krankheitseinheiten") in psychiatry. Notwithstanding contemporary criticism that he commented upon, this concept stayed at the very center of Kraepelin's thinking, and therefore profoundly shaped his clinical nosology.

DSM-5 reviewed from different angles: goal attainment, rationality, use of evidence, consequences—part 2: bipolar disorders, schizophrenia spectrum disorders, anxiety disorders, obsessive-compulsive disorders, trauma- and stressor-related disorders, personality disorders, substance-related and addictive disorders, neurocognitive disorders

Part 1 of this paper discussed several more general aspects of Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and offered a detailed, paradigmatic analysis of changes made to the chapter on depressive disorders. This second part focusses on several other disorders, including bipolar and schizophrenia spectrum disorders. The respective changes and their possible consequences are discussed under consideration of traditional psychiatric classification, particularly from the perspective of European traditions and on the basis of a PubMed search and review papers. The general conclusion is that even seemingly small changes such as the introduction of the mixed feature specifier can have far-reaching consequences. Contrary to the original plans, DSM-5 has not radically changed to become a primarily dimensional diagnostic system but has preserved the categorical system for most disorders. The ambivalence of the respective decision-making becomes apparent from the last minute decision to change the classification of personality disorders from dimensional back to categorical. The advantages and disadvantages of the different approaches are discussed in this context. In DSM-5, only the chapter on addictive disorders has a somewhat dimensional structure. Also in contrast to the original intentions, DSM-5 has not used a more neurobiological approach to disorders by including biological markers to increase the objectivity of psychiatric diagnoses. Even in the most advanced field in terms of biomarkers, the neurocognitive disorders, the primarily symptom-based, descriptive approach has been preserved and the well-known amyloid-related and other biomarkers are not included. This is because, even after so many years of biomarker research, the results are still not considered to be robust enough to use in clinical practice.

[Schizophrenia and other psychotic disorders in DSM-5: summary of the changes compared to DSM-IV]

With the introduction of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) numerous changes in the area of the schizophrenia spectrum and psychotic disorders have been implemented. Establishing a metastructure based on the characteristics of the spectrum of psychopathological disturbances should improve clarity. The classical subtypes of schizophrenia were eliminated and specific psychopathological dimensions for the assessment of disease severity were added. The special role of Schneiderian first rank symptoms was abandoned and a higher delineation towards schizoaffective disorders is made. The nosological status of catatonia is clarified and occurs together with a consistent use of catatonic disturbances over all chapters. The attenuated psychosis syndrome is added as a new condition for further study. The shared psychotic disorder in the sense of a folie à deux is no longer maintained. However, the initial goal to integrate more disorder-specific etiopathogenetic information into the reconceptualization could not be achieved. Contemporaneously to the development process of DSM-5 the National Institute of Mental Health (NIMH) carried out the research domain criteria project (RDoC) attempting to incorporate the current growth in knowledge of genetics, neurocognitive and cognitive sciences in future diagnostic systems. This article gives an overview of the changes that have been made within the revision process from DSM-IV to DSM-5.

Association between symptom dimensions and categorical diagnoses of psychosis: a cross-sectional and longitudinal investigation

CONTEXT

Cross-sectional studies of the signs and symptoms of psychosis yield dimensional phenotypes. However, the validity and clinical utility of such dimensions remain debated. This study investigated the structure of psychotic symptomatology, the stability of the structure over time, and the concordance between symptom dimensions and categorical diagnoses.

METHODS

Sample consisted of 500 first-episode psychotic patients. A cross-sectional study (N = 500) investigated the organizational structure of symptom dimensions at the onset of psychosis and its concordance with categorical diagnoses; next, a nested longitudinal study (N = 100) examined the stability of the symptom dimensions structure after 5-10 years of follow-up.

RESULTS

Factor analyses identified 6 first-order factors (mania, negative, disorganization, depression, hallucinations, and delusions) and 2 high-order factors (affective and nonaffective psychoses). Cumulative variance accounted for by the first and high-order factors was 63%: 31% by the first-order factors and 32% by the high-order factors. The factorial structure of psychotic symptoms during first episode remained stable after 5-10 years of follow-up. The overall concordance between 4 categorical diagnostic groups (schizophrenia, mania with psychosis, psychotic depression and schizoaffective disorder) and dimensional symptom ranged from 62.2% to 73.1% (when the schizoaffective group was excluded).

CONCLUSIONS

Symptoms of psychosis assume a multidimensional hierarchical structure. This hierarchical model was stable over time and showed good concordance with categorical diagnoses. The combined use of dimensional and categorical approach to psychotic disorders would be of clinical and research utility.

Eugen Bleuler's concept of schizophrenia and its relevance to present-day psychiatry

This paper links the historical perspective with the actual debate on the concept of schizophrenia. By this, two aims shall be accomplished. First, to prove that Eugen Bleuler's (1857-1939) concept of 'schizophrenia' in its central parts was a clear step forward, as compared to previous approaches, especially the notion of 'dementia praecox', proposed and favored by French authors like Bénédict Augustin Morel (1809-1873) and, in Germany, by Emil Kraepelin (1856-1926). Bleuler considerably reduced the epistemological presuppositions of Kraepelin's nosological model and coined the term 'group of schizophrenias', which was markedly broader and, as for prognosis, much less pessimistic. The second aim of this paper is to argue in favor of a continuous reflection upon psychiatry's historical and epistemological basis which is regarded not just as 'l'art pour l'art', but as an indispensable component of psychiatry, clinically and scientifically.

The Community Assessment Psychic Experience (CAPE): evaluation study of the Italian version

Negli ultimi anni il modello categoriale della psicosi e della schizofrenia in particolare, è stato riconsiderato a favore di una visione dimensionale. Questa assume che I sintomi psicotici differiscono in modo quantitativo dalle normali esperienze psichiche distribuendosi lungo un continuum che va dalla popolazione clinica affetta da schizofrenia ad individui con disturbo di personalità, fino alla popolazione generale che può mostrare esperienze simil psicotiche (Hanssen et al., 2003; Johns & Phil, 2005). Tale continuità fenomenologica è suggerita da studi che mostrano che le dimensioni del fenotipo della psicosi subclinica sono molto simili a quelle identificate nei disturbi clinici (Van Os et al. 2000; Van Os & Tamminga, 2007; Rossler et al., 2007). Sono state infatti riportate dimensioni positive e negative sia in ambito clinico che subclinico, mentre più incerta appare la presenza della dimensione disorganizzazione (Vollema & Hoijtink, 2000; van Os et al., 2002). Vari studi hanno riportato che i fenotipi clinico e non clinico condividono fattori di rischio, meccanismi psicologici ed i pattern epidemiologici (Sharpley & Peters,1999; Johns & van Os, 2001; van Os et al., 2001), fornendo un'ulteriore prova che l'espressione clinica e subclinica delle psicosi fanno parte dello stesso continuum.

Psychotic-like experiences in major depression and anxiety disorders: a population-based survey in young adults

OBJECTIVE

Population-based surveys have confirmed that psychotic-like experiences are prevalent in the community. However, it is unclear if these experiences are associated with common mental disorders. The aim of this study was to examine the prevalence of psychotic-like experiences in those with affective and anxiety disorders.

METHODS

Subjects were drawn from the Mater-University of Queensland Study of Pregnancy. Delusion-like experiences were assessed with the Peters Delusional Inventory (PDI). The Composite International Diagnostic Interview (CIDI) was used to identify individuals with Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) lifetime diagnoses of major depression, anxiety disorder, substance use/dependence, and psychotic disorders. The influence of affective and anxiety disorders on PDI and CIDI psychosis-related items' scores were assessed with logistic regression, with adjustments for age, sex, and the presence of the other comorbid psychiatric diagnoses.

RESULTS

Having either a lifetime diagnosis of major depressive disorder or an anxiety disorder was associated with significantly higher PDI total scores (highest vs lowest quartile adjusted odds ratios [ORs] and 95% confidence intervals [CIs] = 4.43, 3.09-6.36; 3.08, 2.26-4.20, respectively). The odds of endorsing any CIDI hallucination or delusion item was increased in those with a major depressive or anxiety disorder. The presence of current anxiety disorder symptoms was significantly associated with PDI score (OR = 5.81, 95% CI = 3.68-9.16).

CONCLUSION

While psychotic-like experiences are usually associated with psychotic disorders, individuals with depression and anxiety are also more likely to report these symptoms compared with well individuals. Psychotic-like experiences are associated with a range of common mental disorders.

Diagnostic and prognostic significance of Schneiderian first-rank symptoms: a 20-year longitudinal study of schizophrenia and bipolar disorder

OBJECTIVE

This research addresses the following questions: what is the prevalence and severity of first-rank symptoms (FRS) during an extended period of time in patients with schizophrenia and bipolar disorder with psychosis? Are the specific FRS listed in Diagnostic and Statistical Manual of Mental Disorders DSM, Third Edition, Revised/Fourth Edition Criterion A for schizophrenia diagnosis (a voice keeping a running commentary or voices conversing) more prevalent and severe in patients with schizophrenia than bipolar disorder with psychosis? Lastly, do FRS at index hospitalization in patients with schizophrenia predict the absence of later recovery?

METHODS

This research follows a sample of patients with psychotic disorders who were evaluated at index hospitalization and then prospectively followed-up at 6 evaluations during next 20 years (n = 86). All patients were evaluated as part of a prospective research study designed to measure multiple factors of phenomenology, severity of illness, course of illness, prognosis, and global outcome.

RESULTS

First-rank symptoms are not exclusive to schizophrenia; they also occur in some bipolar patients. However, they are more frequent and more severe in patients with schizophrenia than bipolar disorder. Schizophrenia patients with FRS during the acute phase are more likely to have poorer long-term outcome than schizophrenia patients who do not have FRS during the acute phase.

CONCLUSIONS

Our results indicate FRS at the acute phase are not a clinicopathologic correlate specific to schizophrenia. However, the presence and severity of any FRS and specifically of the 2 FRS associated with Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised/Fourth Edition Criterion A are more prevalent and more severe in patients with schizophrenia than patients with bipolar disorder.

Objectivity and ethics in forensic psychiatry

PURPOSE OF REVIEW

In this paper, we analyze the concept of objectivity as it is accepted in the 'standard position' on ethical practice in forensic psychiatry and confront it with the current trends of psychiatric nosology, specially the debate that we have now regarding the theoretical orientation of DSM-5, which is intended to be more based on neuroscientific more than on clinical data, as has been the tradition in psychiatry so far.

RECENT FINDINGS

In view of those elements, we review the skeptical position about the ethics of forensic psychiatry and the obstacles that, in my opinion, are still standing according to Stone's proposal: the fact-value distinction, determinism vs. free will, the deconstruction of the self, the mind-brain problem, and the chasm between morality and normal science. In my opinion the objections made by Stone on the feasibility of forensic psychiatry in the courts continue in full force, to the extent that these objections are the heart of the debate about the theoretical orientation of the DSM-5.

SUMMARY

The advocates of the standard position have an overly optimistic view of the capacity of objectification of forensic psychiatry. This problem has also been revealed in the intense debates on the direction of the DSM-5 in general psychiatry, a draft of which appears excessively based on neuroscience and little on traditional clinical practice.

Schizophrenia, reification and deadened life

Recent debates concerning the abolition of the schizophrenia label in psychiatry have focused upon problems with the scientific status of the concept. In this article, I argue that rather than attacking schizophrenia for its lack of scientific validity, we should focus on the conceptual history of this label. I reconstruct a specific tradition when exploring the conceptual history of schizophrenia. This is the concern with the question of the sense of life itself, conducted through the confrontation with schizophrenia as a form of life that does not live, or as Robert Jay Lifton termed it "lifeless life" (1979: 222-39). I conclude by arguing that the contemporary attempt to deconstruct or abolish the schizophrenia concept involves a fundamental shift in concern. The attempt both to normalize psychotic experiences, and to conceive them purely in terms of cognitive processes that can be mapped onto brain function, results in a fundamental move away from the attempt to understand the experience of madness.

Development of DSM-V and ICD-11: tendencies and potential of new classifications in psychiatry at the current state of knowledge

A reason for the necessity to revise ICD-10 and DSM-IV is the increase of knowledge in the past 20 years, especially neurobiological knowledge. But is this increase of knowledge, for example in the field of neurogenetics, of such magnitude that a revision of the psychiatric classification is necessary and promises to be fruitful? The current plans for DSM-V or ICD-11, respectively, focus on different improvements. In this context also the introduction of a purely syndromatic/dimensional approach without including etiopathogenetic hypotheses, is discussed. A switch to such a dimensional approach, which was discussed among others in the DSM-V task force Deconstructing Psychosis, would be the most radical development. It could avoid many theoretical pre-assumptions about causal hypotheses, which are still associated with ICD-10 and DSM-IV. This would indeed increase the validity of psychiatric classification, but it would also reduce the information as compared to traditional diagnostic categories with all the current implications concerning etiopathogenesis, therapy and prognosis. Such a dimensional approach would also mean that the syndromes would have to be assessed in a standardized way for each person seeking help from the psychiatric service system or for each person undergoing psychiatric research. This would have to be a multi-dimensional assessment covering all syndromes existing within different psychiatric disorders. Based on the different aspects that must be considered in this context, a careful revision seems more advisable than a radical change of classification.

Psychopathological assessment of schizophrenia: relevance for classification

Considerable effort has been focused on updating the clinical aspects of psychiatric classifications based on recent progress in the field of neurobiology. In this article, recent developments in the primary assessment methods within clinical psychiatry, which are based in phenomenological psychopathology, are reviewed as nosotaxies that are still embedded in clinical description. New directions for research on psychopathology are outlined to elicit better descriptions of subjective experience from patients. Finally, the known limitations of the Kraepelinian dichotomy are summarized, and future problems related to the inclusion of the new dimensional assessment methods in the next psychiatric classifications are described.

Will the Kraepelinian dichotomy survive DSM-V?

Kraepelin proposed dementia praecox and manic-depressive illness as the two major psychotic disorders. This paradigm is still prevalent, but observations of overlapping boundaries between bipolar disorder and schizophrenia challenge this dichotomy. However, the concept of schizophrenia has been radically altered from the original Kraepelinian proposal. We defend the two psychoses positions, but suggest two flaws in the heuristic application: (1) overlapping features, such as psychotic symptoms, are not decisive in differential diagnosis; and (2) each disorder is a syndrome, not a disease entity. An alternative paradigm based on domains of pathology is more powerful for studies of etiology, pathophysiology, and therapeutic discovery.

Ethnicity and variability of psychotic symptoms

This review addresses the influence of ethnicity on the expression of psychotic symptoms and the implications for evaluating and treating patients of diverse backgrounds. Growing clinical and population research from Europe and the United States supports a dimensional interpretation of psychosis, yet the evidence suggests that psychotic symptoms place individuals at higher risk for a range of severe psychiatric conditions and adverse outcomes, such as suicidality. Ethnocultural diversity challenges clinicians to accurately interpret the clinical significance of patients' symptom presentations. Disproportionate psychotic symptoms and higher rates of psychotic disorders have been found in some ethnic groups, particularly among immigrants and their offspring, but profound inconsistencies in these patterns remain. More cultural research on the clinical implications of ethnic variation in psychosis is needed. Developing awareness and requisite skills is a priority for clinicians who evaluate and recommend treatments to ethnically diverse patients.