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

Productivity costs of schizophrenia spectrum and other psychotic disorders by friction cost and human capital methods: The Northern Finland Birth Cohort 1966

PURPOSE

Psychotic disorders are associated with substantial productivity costs; however no previous studies have compared these between schizophrenia spectrum (SSD) and other psychotic disorders (OP). The human capital method (HCM) and the friction cost method (FCM) are the two most common approaches to assess productivity costs. The HCM focuses on employees' perspectives on the costs, whereas the FCM demonstrates employers' perspectives. Studies comparing these methods when estimating the productivity costs of psychoses are lacking.

METHODS

Utilizing the Northern Finland Birth Cohort 1966 with linkages to national registers, we compared the adjusted productivity costs of SSD (n = 216) and OP (n = 217). The productivity costs were estimated from ages 18 to 53 including projections to statutory retirement age using the FCM and HCM.

RESULTS

When estimated via the HCM, productivity losses were higher for SSD (€193,940) than for OP (€163,080). However, when assessed using the FCM, costs were significantly lower for SSD (€2,720) than for OP (€4,430). Productivity costs varied by sex and various clinical and occupational factors.

CONCLUSION

This study highlights how productivity costs vary by psychosis diagnosis. These differences should be noted when planning interventions. The low FCM estimates indicate the need of interventions before or during the early phases of psychoses. From a societal perspective, interventions are needed, particularly for those with highest HCM productivity losses, such as males with SSD. Besides psychiatric services, the roles of social services, employment agencies and occupational health care should be considered when helping individuals with psychoses to working life.

The prognosis of schizophrenia: A systematic review and meta-analysis with meta-regression of 20-year follow-up studies

OBJECTIVE

The aim was to examine the general outcome of schizophrenia after 20 years or more.

METHODS

Using the PRISMA guidelines, we conducted a systematic review and meta-analysis with meta-regression on long-term follow-up studies of schizophrenia up until April 21, 2021. We included prospective studies with at least 20 years of follow-up on patients with a diagnosis of schizophrenia, and the studies had to include face-to-face clinical evaluation. We examined outcome in three nested groups: 'recovery', 'good or better' (including also 'recovery'), and 'moderate or better' (including also 'recovery' and 'good or better'). We used random-effects meta-analysis and meta-regression to examine mean estimates and possible moderators.

RESULTS

We identified 1089 records, which were screened by two independent researchers. 14 prospective studies (1991 patients) published between 1978 and 2020 were found eligible. The studies used a range of different scales and definitions for outcome, and some used the same definitions for different outcomes. To compare outcome across studies, we designed and applied a unified template for outcome definitions and cutoffs, based on earlier studies' recommendations. Our meta-analysis found that 24.2 % had 'recovered' (n = 246, CI: 20.3-28.0 %), 35.5 % had a 'good or better' outcome (n = 766, CI: 26.0-45.0%), and 59.7% had 'moderate or better' outcome (n = 1139, CI: 49.3-70.1 %).

CONCLUSIONS

The results contribute to debunk the myth that schizophrenia inevitably has a deteriorating course. Recovery is certainly possible. Schizophrenia remains, however, a severe and complex mental disorder, exhibiting a limited change in prognosis despite >100 years of research and efforts to improve treatment.

We are not ready to abandon the current schizophrenia construct, but should be prepared to do so

The current schizophrenia construct as delineated in the latest editions of the DSM and the ICD has some strengths, but also many weaknesses. It improved the reliability of the diagnosis, made communication among clinicians, users and families less ambiguous, is useful for education and training, and for reimbursement and insurance purposes. However, many serious weaknesses should be considered. The term "Schizophrenia" does not recognize the heterogeneity of the disorder and might nourish the belief that schizophrenia represents a unitary disease. In addition, there is no agreement on the existence and nature of a "core aspect" of the disorder. Stable dimensions, in particular negative symptoms and cognitive impairment, which are key determinants of functioning, are not de facto regarded as core aspects. Finally, the construct is associated to the notion of a poor outcome, to a high level of stigma and has acquired a derogatory connotation. We are not ready but should be prepared to abandon the current schizophrenia construct. Clinicians and researchers should be encouraged to complement the ICD/DSM diagnosis with an in-depth characterization of the individual clinical picture, along with other variables, such as family history, comorbidities, vulnerability factors and personal trajectory. The "Primary Psychoses" construct, together with improved cross-sectional and longitudinal phenotypes from representative population and patient cohorts, and the availability of artificial intelligence methods, could lead to a new and more precise taxonomy of psychotic disorders, and increase the probability of identifying meaningful biomarkers to improve prevention, diagnosis, prognosis, and treatment for people suffering from psychotic disorders.

An organization- and category-level comparison of diagnostic requirements for mental disorders in ICD-11 and DSM-5

In 2013, the American Psychiatric Association (APA) published the 5th edition of its Diagnostic and Statistical Manual of Mental Disorders (DSM-5). In 2019, the World Health Assembly approved the 11th revision of the International Classification of Diseases (ICD-11). It has often been suggested that the field would benefit from a single, unified classification of mental disorders, although the priorities and constituencies of the two sponsoring organizations are quite different. During the development of the ICD-11 and DSM-5, the World Health Organization (WHO) and the APA made efforts toward harmonizing the two systems, including the appointment of an ICD-DSM Harmonization Group. This paper evaluates the success of these harmonization efforts and provides a guide for practitioners, researchers and policy makers describing the differences between the two systems at both the organizational and the disorder level. The organization of the two classifications of mental disorders is substantially similar. There are nineteen ICD-11 disorder categories that do not appear in DSM-5, and seven DSM-5 disorder categories that do not appear in the ICD-11. We compared the Essential Features section of the ICD-11 Clinical Descriptions and Diagnostic Guidelines (CDDG) with the DSM-5 criteria sets for 103 diagnostic entities that appear in both systems. We rated 20 disorders (19.4%) as having major differences, 42 disorders (40.8%) as having minor definitional differences, 10 disorders (9.7%) as having minor differences due to greater degree of specification in DSM-5, and 31 disorders (30.1%) as essentially identical. Detailed descriptions of the major differences and some of the most important minor differences, with their rationale and related evidence, are provided. The ICD and DSM are now closer than at any time since the ICD-8 and DSM-II. Differences are largely based on the differing priorities and uses of the two diagnostic systems and on differing interpretations of the evidence. Substantively divergent approaches allow for empirical comparisons of validity and utility and can contribute to advances in the field.

Childhood schizotypal features vs. high-functioning autism spectrum disorder: Developmental overlaps and phenomenological differences

Although autism spectrum disorder and schizophrenia have allegedly different onset timelines (e.g. in early years of life vs adolescence/early adulthood), there is nonetheless a diagnostic grey-zone along developmental stages, in which overlapping clinical features related to social impairment and oddity could impact on the differential diagnosis between childhood schizotypal features and high-functioning autism spectrum disorder. A phenomenological perspective may be helpful for the purpose of timely differential diagnosis also in developmental years.

Risk of schizophrenia in relatives of individuals affected by schizophrenia: A meta-analysis

A meta-analysis was conducted to estimate schizophrenia incidence in first-degree relatives (FDRs) of probands diagnosed with schizophrenia. The aim was to inform future schizophrenia research and improve accuracy of risk communication to patients. Schizophrenia risk in FDRs with 1 or 2 probands with schizophrenia was investigated by conducting a systematic review of cohort and case-control studies with the following criteria: published between 1977 and 2018; reported odds ratios (OR), relative risk (RR) or sufficient raw data to calculate OR or RR; used appropriate diagnostic criteria; and reported systematic proband recruitment and ascertainment of relatives. Studies were obtained via EMBASE and MEDLINE electronic database searches. From an initial 5755 articles, 19 met the inclusion criteria. Mean effect sizes across studies were estimated using random effects methods. Estimates for schizophrenia risk were OR = 7.69 (95% CI 5.11-11.56) for FDRs of one proband with schizophrenia compared to healthy control probands, increasing to OR = 11.11 (95% CI = 1.45-85.02) for FDRs with two probands with schizophrenia. These findings support the existing literature suggesting significant genetic liability for schizophrenia. The results can be used to educate individuals with a family history of schizophrenia about their risk.

A reflection upon methods to explore timing in patients with schizophrenia

Phenomenologists have provided a detailed description of the disorders of the subjective experience associated with minimal-self disorders in patients with schizophrenia. Those patients report a range of distortions of their conscious experiences, including a sense of inner void, confusion between self and others, and, sometimes, a disruption of the sense of time. These reports have been interpreted as distortion of the first-person perspective and a lack of immersion in the world, associated with a breakdown of the temporal structure of consciousness, and especially a disruption of the sense of time continuity. Further, it has been proposed that these disruptions are based on a difficulty to retain past information and to predict future information, that is, the mechanisms that help to relate events with one another and to reach a sense of time continuity. Experimental psychology results seem to converge to similar conclusions, inasmuch as some results in patients with schizophrenia suggest a deficient ability to predict sequences of events at the millisecond level. Several studies have underlined this convergence. Here we reflect on the limits of both the phenomenological and experimental psychology approaches, and of the convergence of their hypotheses. We think that this reflection is necessary to avoid premature conclusions on the mechanisms underlying the impairments in patients, but also to enrich our understanding of schizophrenia.

Because space matters: conceptual framework to help distinguish slum from non-slum urban areas

Despite an estimated one billion people around the world living in slums, most surveys of health and well-being do not distinguish between slum and non-slum urban residents. Identifying people who live in slums is important for research purposes and also to enable policymakers, programme managers, donors and non-governmental organisations to better target investments and services to areas of greatest deprivation. However, there is no consensus on what a slum is let alone how slums can be distinguished from non-slum urban precincts. Nor has attention been given to a more fine-grained classification of urban spaces that might go beyond a simple slum/non-slum dichotomy. The purpose of this paper is to provide a conceptual framework to help tackle the related issues of slum definition and classification of the urban landscape. We discuss:The concept of space as an epidemiological variable that results in 'neighbourhood effects'.The problems of slum area definition when there is no 'gold standard'.A long-list of variables from which a selection must be made in defining or classifying urban slum spaces.Methods to combine any set of identified variables in an operational slum area definition.Two basic approaches to spatial slum area definitions-top-down (starting with a predefined area which is then classified according to features present in that area) and bottom-up (defining the areal unit based on its features).Different requirements of a slum area definition according to its intended use.Implications for research and future development.

Subclinical high schizotypy traits are associated with slower change detection

Patients with schizophrenia often show impairments in visual information processing that have been linked to abnormal magnocellular or dorsal stream functioning. However, such deficits are not consistently reported, possibly due to the broad symptomology inherent to schizophrenia, and/or medication effects. To avoid these latter issues this study employed visual perceptual tasks targeting magnocellular (flicker-defined form contrast threshold), dorsal stream (motion coherence, change detection) and ventral stream (form coherence) processing, and compared performance of groups of high and low sub-clinical schizotypy traits from a neurotypical population (n = 20 per group). Significantly worse performance of high compared with low schizotypy participants was only demonstrated on the change detection task that requires rapid attention acquisition and encoding of the first visual array into short term memory prior to a comparison of a second array presentation. No group differences on the other tasks were established. Given this potentially important effect is apparent in a non-clinical population, there are likely to be implications for understanding visual and attentional abnormalities in the schizophrenia spectrum more broadly.

Genetics of Schizophrenia: Overview of Methods, Findings and Limitations

Genetics constitute a crucial risk factor to schizophrenia. In the last decade, molecular genetic research has produced novel findings, infusing optimism about discovering the biological roots of schizophrenia. However, the complexity of the object of inquiry makes it almost impossible for non-specialists in genetics (e.g., many clinicians and researchers) to get a proper understanding and appreciation of the genetic findings and their limitations. This study aims at facilitating such an understanding by providing a brief overview of some of the central methods and findings in schizophrenia genetics, from its historical origins to its current status, and also by addressing some limitations and challenges that confront this field of research. In short, the genetic architecture of schizophrenia has proven to be highly complex, heterogeneous and polygenic. The disease risk is constituted by numerous common genetic variants of only very small individual effect and by rare, highly penetrant genetic variants of larger effects. In spite of recent advances in molecular genetics, our knowledge of the etiopathogenesis of schizophrenia and the genotype-environment interactions remain limited.

Is schizophrenia disappearing? The rise and fall of the diagnosis of functional psychoses: an essay

BACKGROUND

The categories of functional psychoses build on views of influential professionals. There have long been four main categories - affective, schizophrenic, schizoaffective/cycloid/reactive/polymorphic, and delusional/paranoid psychoses. The last three are included in "psychotic disorders". However, this dichotomy and the distinctions between categories may have been over-estimated and contributed to lack of progress.

TEN TOPICS RELEVANT FOR THE DIAGNOSIS OF FUNCTIONAL PSYCHOSES

1. The categories of functional psychoses have varied with time, place and professionals' views, with moving boundaries, especially between schizophrenia and affective psychoses. 2. Catatonia is most often related to affective and organic psychoses, and paranoia is related to grandiosity and guilt, calling in question catatonic and paranoid schizophrenia. Arguments exist for schizophrenia being a "misdiagnosis". 3. In some countries schizophrenia has been renamed, with positive consequences. 4. The doctrine of "unitary psychosis", which included abnormal affect, was left in the second half of the 1800s. 5. This was followed by a dichotomy between schizophrenia and affective psychoses and broadening of the schizophrenia concept, whereas affective symptoms were strongly downgraded. 6. Many homogeneous psychoses with mixtures of schizophrenic and affective symptoms were described and related to "psychotic disorders", although they might as well be affective disorders. 7. Critique of the extensive schizophrenia concept led to, in DSM-III and ICD-10, affective symptoms being exclusion criteria for schizophrenia and acceptance of mood-incongruent psychotic symptoms in affective psychoses. 8. However, affective symptoms are often difficult to acknowledge, diagnosis is often done on the basis of tradition and previous education, and patients' affect characterized accordingly. 9. DSM-5 is up-dated with separate chapters for catatonia and psychotic symptoms, and removal of the subtypes of schizophrenia. However, time may be running out for categorical psychosis diagnoses, which may be replaced by continuum, spectrum, dimensional and research domain criteria, in line with new biological data 10. This is supported by treatment responses across categories.

CONCLUSION

The time-consuming works on diagnosis of psychoses may have hampered progress. Chronic mood disorders may appear as schizophrenic or paranoid psychosis, end-stages like heart failure in heart diseases. This underscores the importance of early and optimal treatment of mood disorders.

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.

Impact of DSM-5 changes on the diagnosis and acute treatment of schizophrenia

OBJECTIVE

To examine the consequences and validity of changes in Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 diagnostic criteria for schizophrenia, eg, omission of subtypes, using a large dataset of double-blind, randomized, placebo-controlled schizophrenia trials.

METHODS

Data from 22 short-term efficacy registration trials of second generation antipsychotics for the treatment of acute psychotic episodes in patients with schizophrenia (N = 5233), submitted to the Dutch regulatory authority were analyzed. We examined whether patients in these pre-DSM-5 trials met the diagnostic criteria for schizophrenia according to DSM-5. Using linear regression, we examined differences in effect size between DSM-IV subtypes and between DSM-5 symptom dimensions.

RESULTS

Over 99.5% of the patients met DSM-5 diagnostic criteria for schizophrenia and no differences in effect size were found between schizophrenia subtypes (P = .65). Symptom dimensions that respond best to treatment with second generation antipsychotics were hallucinations, delusions, disorganized speech, and mania (Hedge's g -0.23 to -0.31).

CONCLUSIONS

Results of clinical trials in patients with pre-DSM-5 schizophrenia also apply to patients diagnosed with DSM-5 schizophrenia. Omission of the classic subtypes is justified as they are not predictive of response to treatment. The DSM-5 C-RDPSS scale adds valuable information to the categorical diagnosis of schizophrenia, which is relevant for antipsychotic response.

Self-Disorders: Clinical and Conceptual Implications for the Diagnostic Concept of Schizophrenia

The release of DSM-5 and the preparations for the launch of the ICD-11 provoked a series of critiques of psychiatric classification, which continues to depend largely on clinical description. Among the immediate problems are those of arbitrary diagnostic thresholds, tendency to reification, rigid category boundaries, comorbidity, diagnostic 'epidemics' and differential diagnostic dilemmas. We argue that many of those problems stem from the polythetic-operational definitions of psychiatric categories, which thereby come to lack an organizing prototype-directed or gestaltic intelligibility principle. We illustrate these issues by briefly examining the current operational diagnosis of schizophrenia, its demarcation from affective illness and the status of the spectrum concept and the prodrome of schizophrenia. We point out that European research on schizophrenia always allocated an important diagnostic weight to a certain prototypical trait core of the illness, phenomenologically indispensable for its demarcation from other, nonschizophrenic psychotic conditions. We believe that the notion of self-disorder (reflective of the structural alterations of subjectivity), itemized into its various aspects in the Examination of Anomalous Self-Experience scale, is an important step forward in a more precise psychopathological articulation of that core, strengthening its clinical and research utility.

Mismatch negativity: translating the potential

The mismatch negativity (MMN) component of the auditory event-related potential has become a valuable tool in cognitive neuroscience. Its reduced size in persons with schizophrenia is of unknown origin but theories proposed include links to problems in experience-dependent plasticity reliant on N-methyl-d-aspartate glutamate receptors. In this review we address the utility of this tool in revealing the nature and time course of problems in perceptual inference in this illness together with its potential for use in translational research testing animal models of schizophrenia-related phenotypes. Specifically, we review the reasons for interest in MMN in schizophrenia, issues pertaining to the measurement of MMN, its use as a vulnerability index for the development of schizophrenia, the pharmacological sensitivity of MMN and the progress in developing animal models of MMN. Within this process we highlight the challenges posed by knowledge gaps pertaining to the tool and the pharmacology of the underlying system.

Definition and description of schizophrenia in the DSM-5

Although dementia praecox or schizophrenia has been considered a unique disease for over a century, its definitions and boundaries have changed over this period and its etiology and pathophysiology remain elusive. Despite changing definitions, DSM-IV schizophrenia is reliably diagnosed, has fair validity and conveys useful clinical information. Therefore, the essence of the broad DSM-IV definition of schizophrenia is retained in DSM-5. The clinical manifestations are extremely diverse, however, with this heterogeneity being poorly explained by the DSM-IV clinical subtypes and course specifiers. Additionally, the boundaries of schizophrenia are imprecisely demarcated from schizoaffective disorder and other diagnostic categories and its special emphasis on Schneiderian "first-rank" symptoms appears misplaced. Changes in the definition of schizophrenia in DSM-5 seek to address these shortcomings and incorporate the new information about the nature of the disorder accumulated over the past two decades. Specific changes in its definition include elimination of the classic subtypes, addition of unique psychopathological dimensions, clarification of cross-sectional and longitudinal course specifiers, elimination of special treatment of Schneiderian 'first-rank symptoms', better delineation of schizophrenia from schizoaffective disorder, and clarification of the relationship of schizophrenia to catatonia. These changes should improve diagnosis and characterization of individuals with schizophrenia and facilitate measurement-based treatment and concurrently provide a more useful platform for research that will elucidate its nature and permit a more precise future delineation of the 'schizophrenias'.

Connecting the dots: applications of network medicine in pharmacology and disease

In 2011, >2.5 million people died from only 15 causes in the United States. Ten of these involved complex or infectious diseases for which there is insufficient knowledge or treatment, such as heart disease, influenza, and Alzheimer's disease.(1) Complex diseases have been difficult to understand due to their multifarious genetic and molecular fingerprints, while certain infectious agents have evolved to elude treatment and prophylaxis. Network medicine provides a macroscopic approach to understanding and treating such illnesses. It integrates experimental data on gene, protein, and metabolic interactions with clinical knowledge of disease and pharmacology in order to extend the understanding of diseases and their treatments. The resulting "big picture" allows for the development of computational and mathematical methods to identify novel disease pathways and predict patient drug response, among others. In this review, we discuss recent advances in network medicine.

Does change in definition of psychotic symptoms in diagnosis of schizophrenia in DSM-5 affect caseness?

Psychotic symptoms are a central element in the diagnosis of schizophrenia, although their precise definition has varied through the multiple iterations of DSM and the ICD. Schneiderian first-rank symptoms (FRS) have received a particularly prominent position in the diagnostic criteria of schizophrenia since ICD-9 and DSM-III. In the current iteration of DSM (DSM-IV-TR), whereas two characteristic symptoms are ordinarily required to meet criterion A, only a single symptom is necessary if the psychotic symptom happens to be a FRS, notably a bizarre delusion or auditory hallucination of a running commentary or 'conversing voices'. Because of limited data in support of the special treatment of FRS, DSM-5 has made changes to criterion A, requiring that at least two psychotic symptoms be present in all cases with at least one of these symptoms being a delusion, hallucination, or disorganized speech. To assess the impact of these changes on the prevalence of schizophrenia, we examined a research dataset of 221 individuals with DSM-IV schizophrenia to study the prevalence and co-occurrence of various criterion A symptoms. Although bizarre delusions and/or Schneiderian hallucinations were present in 124 patients (56.1%), they were singly determinative of diagnosis in only one patient (0.46%). Additionally, only three of the 221 patients (1.4%) with DSM-IV schizophrenia did not have a delusion, hallucination, or disorganized speech. DSM-5 changes in criteria A should have a negligible effect on the prevalence of schizophrenia, with over 98% of individuals with DSM-IV schizophrenia continuing to receive a DSM-5 diagnosis of schizophrenia in this dataset.

Repetitive transcranial magnetic stimulation (rTMS) for treating major depression and schizophrenia: a systematic review of recent meta-analyses

BACKGROUND

In recent years, repetitive transcranial magnetic stimulation (rTMS) has been developed for the treatment of major depression (MD) and schizophrenia. Although rTMS has shown some promising findings, the lack of standardization in the methodology employed has resulted in discordant findings.

OBJECTIVES

The objective of this systematic review was to summarize several meta-analytical studies exploring the efficacy of rTMS in either MD or schizophrenia in order to examine the methodologies that increase the efficacy of rTMS and to provide some recommendations for future studies.

METHODS

We searched the MEDLINE database for potentially relevant meta-analytic studies on the use of rTMS for treating major depression and schizophrenia published from January 2000 to October 2011.

RESULTS

Fifteen rTMS meta-analytical studies were reviewed (11 on MD and 5 on schizophrenia). Several variables were reviewed including outcome measures, side-effects of rTMS, site of stimulation, frequency and intensity of stimulation, and number of treatment sessions.

CONCLUSIONS

Overall, rTMS appears to be an effective and promising therapeutic for both MD and schizophrenia.

Has the prevalence, clinical presentation and social functioning of schizophrenia changed over the last 25 years? Nithsdale schizophrenia survey revisited

BACKGROUND

Major changes in the treatment of schizophrenia have taken place in recent years, including a shift from inpatient to community care, and the introduction of second-generation antipsychotics and psychosocial interventions. Recent evidence has questioned the superiority of these interventions over older treatments.

AIMS

We wished to ascertain the impact of changes in the treatment of schizophrenia in a geographically-defined area, focusing on clinical symptoms and psychosocial outcome.

METHODS

In 2006, we replicated the survey carried out in 1981, identifying the population of people with schizophrenia living in Nithsdale, South-West Scotland, measuring prevalence using the 'key informant' method. We assessed their clinical and social functioning, using similar scales, and compared measures across both time periods.

RESULTS

We identified 205 people with schizophrenia, a point prevalence of 3.59/1000 general population. In 2006, while fewer people experienced negative symptoms, a greater number experienced positive symptoms. There were no significant differences in the prevalence of tardive dyskinesia or Parkinsonism, though tremor was less common in the 2006 population. In 2006, there were fewer people living with a spouse/partner or parents, and fewer were in open employment in comparison to the 1981 population. The overall level of social adjustment had not changed.

CONCLUSIONS

The clinical manifestation of schizophrenia appears to have changed over the last 25 years, within this geographically-defined area, the prevalence of negative symptoms having decreased, and positive symptoms seem to have increased. The level of social functioning does not appear to have changed over the last 25 years.

Heterogeneity and symptom structure of schizophrenia

Previous studies failed to identify a consistent factor structure of the BPRS-24 in schizophrenia. Our aims were to examine the fit of all previously published factor models and then to explore unobserved population heterogeneity and identify salient latent classes. Two hundred thirty-nine patients with ICD-10 schizophrenia admitted to a random sample of all Italian public and private acute inpatient units during an index period were administered the BPRS-24. Confirmatory factor analysis (CFA) was used to test all factor models derived in previous studies. Then, factor mixture analysis (FMA) with heteroscedastic components was carried out to explore unobserved population heterogeneity. No previously reported factor solution showed adequate fit in CFA. FMA indicated the presence of three heterogeneous groups and yielded a 5-factor solution (Depression, Positive Symptoms, Disorganization, Negative Symptoms, Activation). Group 1 was characterized by higher Disorganization, lower Activation, lower psychosocial functioning, greater lifetime number of admissions, more frequent history of compulsory admission. Group 2 displayed lower Disorganization. Group 3 showed higher Activation and more frequent history of recent self-harming behavior. Our finding that a reliable factor structure for the BPRS-24 could be obtained only after assuming population heterogeneity suggests that the difficulty in identifying a consistent factor structure may be ascribed to the clinical heterogeneity of schizophrenia. As compared with clinical subtypes, the psychopathological dimensions displayed much greater discriminatory power between groups identified by FMA. Though preliminary, our findings corroborate that a dimensional approach to psychopathology can facilitate the assessment of the clinical heterogeneity of schizophrenia.

Core dysfunction in schizophrenia: electrophysiology trait biomarkers

OBJECTIVE

Core symptoms of schizophrenia, particularly in the cognitive domain are hypothesized to be due to an abnormality in neural connectivity. Biomarkers of connectivity may therefore be a promising tool in exploring the aetiology of schizophrenia. We used electrophysiological methods to demonstrate abnormal visual information processing during in patients performing a simple cognitive task.

METHOD

Electrophysiological recordings were acquired from 20 chronically ill, medicated patients diagnosed with either schizophrenia or schizo-affective disorder and 20 healthy volunteers while they conducted a working memory (WM) task.

RESULTS

The patient group had significantly lower accuracy on the WM task and a trend for slower responses. An early visual evoked response potential was reduced in patients. Analysis of the electroencephalographic oscillations showed a decreased phase-locking factor (in the theta, beta and gamma bands) and signal power (theta frequency band). The beta and gamma oscillatory abnormalities were confined to two sets of correlated fronto and occipital electrodes.

CONCLUSION

The findings of event-related potential and oscillatory abnormalities in patients with schizophrenia confirm the sensitivity of early visual information processing measurements for identification of schizophrenia phenotype. The fronto-occipital distribution of the oscillatory abnormalities replicates our findings from a schizotypal sample and implicates a possible top-down dysfunction as a vulnerability trait.

Definitions of schizophrenia, 1908–1987: The failed essentialism

This work examines the historical conceptualization of schizophrenia through definition from 1908–1987. Rather than reveal an essentialist definition of schizophrenia in North America, it reveals a history of varying and competing professional definitions. It demonstrates and historically contextualizes how widespread conceptual instability and disagreement over the nature of the concept gave rise to a new, but still contested, theoretical emphasis on operational definitions. As made manifest through definition, schizophrenia has not been a stable transhistorical object. Rather, the characteristic feature in schizophrenia definition appears to be instability and variance rather than stability or long historical periods of agreement. This analysis nevertheless cautions against overstating the importance of fluctuating definition in assessing the ontological status of contemporary interpretations of schizophrenia.

Evaluation of state and trait biomarkers in healthy volunteers for the development of novel drug treatments in schizophrenia

Antipsychotic drugs are the mainstay of treatment for schizophrenia but they have little effect on core negative symptoms or cognitive impairment. To meet the deficiencies of current treatments, novel potential compounds are emerging from preclinical research but translation to clinical success has been poor. This article evaluates the possibility that cognitive and physiological abnormalities in schizophrenia can be used as central nervous system biomarkers to predict, in healthy volunteers, the likely efficacy of entirely new pharmacological approaches to treatment. Early detection of efficacy would focus resource on rapidly developing, effective drugs. We review the relevance of selected cognitive and physiological abnormalities as biomarkers in schizophrenia and three of its surrogate populations: (i) healthy volunteers with high trait schizotypy; (ii) unaffected relatives of patients; and (iii) healthy volunteers in a state of cortical glutamate disinhibition induced by low-dose ketamine. Several biomarkers are abnormal in these groups and in some instances there has been exploratory work to determine their sensitivity to drug action. They are generally insensitive to current antipsychotics and therefore their predictive validity cannot be established until novel, therapeutically useful drugs are discovered. Until then such biomarker studies can provide evidence of drugs engaging with the mechanism of interest and encouragement of the concept.

The silent side of the spectrum: schizotypy and the schizotaxic self

The identification of individuals carrying unexpressed genetic liability to schizophrenia is crucial for both etiological research and clinical risk stratification. Subclinical psychopathological features detectable in the nonpsychotic part of the schizophrenia spectrum could improve the delineation of informative vulnerability phenotypes. Inspired by Meehl's schizotaxia-schizotypy heuristic model, we tested anomalous subjective experiences (self-disorders, SDs) as a candidate vulnerability phenotype in a sample of nonpsychotic, genetically high-risk subjects. A total of 218 unaffected members of 6 extended multiplex families (assessed between 1989 and 1999 during the Copenhagen Schizophrenia Linkage Study) were stratified into 4 groups of increasing psychopathological expressivity: no mental illness (NMI), no mental illness with schizotypal traits (NMI-ST), personality disorders not fulfilling other personality disorders (OPDs), and schizotypal personality disorder (SPD). We tested the distribution of SDs among the subgroups, the effect of SDs on the risk of belonging to the different subgroups, and the effect of experimental grouping and concomitant psychopathology (ie, negative symptoms (NSs) and subpsychotic formal thought disorder [FTD]) on the chances of experiencing SDs. SDs distribution followed an incremental pattern from NMI to SPD. SDs were associated with a markedly increased risk of NMI-ST, OPDs, or SPD. The odds of SDs increased as a function of the diagnostic category assignment, independently of sociodemographics and concomitant subclinical psychopathology (NSs and FTD). The results support SDs as an expression of schizotaxic vulnerability and indicate a multidimensional model of schizotypy--characterized by SDs, NSs, FTD--as a promising heuristic construct to address liability phenotypes in genetically high-risk studies.

New visual information processing abnormality biomarker for the diagnosis of Schizophrenia

INTRODUCTION: Schizophrenia is currently diagnosed on the basis of patient reports and clinical observations. A diagnosis based on aetiology is inherently more reliable due to being closer to the disease process than the overt clinical manifestations. Accordingly, recent research in schizophrenia has focused on the development of biomarkers in a bit to improve the reliability and neurobiological relevance of the diagnosis. Visual information processing is one of these promising fields of recent biomarker research. AREAS COVERED: This article provides an overview of the available literature regarding deficits in schizophrenia detectable through psychophysical (contrast and motion sensitivity, visual backward-masking), ERP (P1 and N1 visual evoked potentials) and oscillatory (signal power and phase-locking factor of evoked oscilations) measures and their validity as trait or state biomarkers of the disease. The methodology included a search on articles related to visual information processing in schizophrenia on the PubMed database. EXPERT OPINION: Biomarker research in schizophrenia is a rapidly expanding area. Evidence exists to suggest that both psychotic and manic symptoms are associated with visual processing abnormalities. A specific impairment confined to the magnocellular component of the visual system might be a trait biomarker of schizophrenia.

The postpartum depression screening scale: is it valid to screen for antenatal depression?

The purpose of the study was to analyse for the first time the validity of a slightly modified version of the Portuguese Postpartum Depression Screening Scale (PDSS), to be used as a screening instrument for antenatal depression. Specifically, the aims were to analyse its psychometric properties, to determine PDSS cutoff points and associated conditional probabilities to screen for depression according to DSM-IV and ICD-10 criteria and to compare its screening performance with that of the Beck Depression Inventory-II (BDI-II). Five hundred and three pregnant women in the third trimester of pregnancy completed both questionnaires and were interviewed face-to-face with the Portuguese version of the Diagnostic Interview for Genetic Studies. The Portuguese version of the Operational Criteria Checklist for Psychotic Illness was used to obtain DSM-IV and ICD-10 diagnoses of depression, our gold standards for caseness. PDSS reliability and validity were very good and comparable to those obtained in the postpartum validation studies developed in Portugal and in other countries, showing satisfactory sensitivity and specificity combinations (≅80%). Compared with BDI-II, it has the advantage of being more specific for the motherhood context. Although developed for postpartum depression, PDSS is accurate to screen for antenatal depression, and it could be very useful for clinical and epidemiologic purposes.

The Munich 15-year follow-up study (MUFUSSAD) on first-hospitalized patients with schizophrenic or affective disorders: assessing courses, types and time stability of diagnostic classification

OBJECTIVE

In the context of the development of DSM-V and ICD-11 it appears to be useful to get further data on the validity of the diagnostic differentiation between schizophrenic and affective disorders. This study investigated the relevance of the main diagnostic groups schizophrenia, schizoaffective psychosis and affective disorder in the context of different diagnostic systems (ICD-9, ICD-10, DSM -IV), assessing their time stability, long-term courses, types and functional outcome.

METHODS

A total of 323 first hospitalized inpatients of the Psychiatric Department of the University Munich were recruited at index time. The full follow-up evaluation including standardized assessment procedures could be performed in 197 patients.

RESULTS

The re-diagnosis of the patients' disorders shows that with the transition from ICD-9 to ICD-10 or DSM-IV, the group of affective disorders increased numerically while the diagnostic groups of schizophrenia and schizoaffective disorders decreased in size. The structured clinical interview for DSM-IV (SCID) analysis showed that altogether ICD-10 and DSM-IV had a relatively high diagnostic stability. Of the patients with an ICD-10 diagnosis of schizophrenia, 57% had a chronic course; 61% of the patients with a DSM-IV diagnosis of schizophrenia. Patients with affective disorders, according either to ICD-10 or DSM-IV, had in more than 90% of the cases an episodic-remitting course. In terms of prediction of long-term outcome regarding the differentiation between chronic and non-chronic course, the ICD-10 diagnoses did give a slightly better predictive result than a dimensional approach based on the key psychopathological syndrome scores.

CONCLUSIONS

The differentiation between schizophrenic and affective disorders seems meaningful especially under predictive aspects. A dimensional syndromatological description does not exceed the predictive power of the investigated main diagnostic categories, but might increase the clinically relevant information.

Systematic reviews of categorical versus continuum models in psychosis: evidence for discontinuous subpopulations underlying a psychometric continuum. Implications for DSM-V, DSM-VI, and DSM-VII

Diagnostic systems, phenotype models, and theories of etiology incorporate propositions on the underlying nature of psychosis and schizophrenia phenotypes. These propositions, whether implicit or explicit, are that the distributions of the phenotypes, or the phenotype experiences themselves, are dimensional or categorical. On one hand, evidence on the epidemiology of schizophrenia phenotypes suggests symptom phenotypes may not be bound by conventional diagnostic thresholds but instead may blend imperceptibly with subclinical, statistically frequent experience, supporting continuum viewpoints. On the other hand, evidence on the population structure suggests a latent categorical structure; the population may be composed of two types of people. However, both sets of evidence are beset by methodological limitations that point unequivocally to the need to move beyond current diagnostic conceptualizations, observation, and anamnesis of psychosis, and toward responsive and scientifically refutable formulations of schizophrenia.

First-rank symptoms in schizophrenia: reexamining mechanisms of self-recognition

Disturbances of self are a common feature of schizophrenic psychopathology, with patients reporting that their thoughts and actions are controlled by external forces, as shown in first-rank symptoms (FRS). One widely accepted explanatory model of FRS suggests a deficiency in the internal forward model system. Recent studies in the field of cognitive sciences, however, have generated new insights into how complex sensory and motor systems contribute to the sense of self-recognition, and it is becoming clear that the forward model conceptualization does not have unique access to representations about the self. We briefly evaluate the forward model explanation of FRS, reassess the distinction made between the sense of agency and body ownership, and outline recent developments in 4 domains of sensory-motor control that have supplemented our understanding of the processes underlying the sense of self-recognition. The application of these findings to FRS will open up new research directions into the processes underlying these symptoms.

Staging in neuropsychiatry: a heuristic model for understanding, prevention and treatment

The main mental disorders which develop and persist through adult life typically emerge during the critical developmental phase of adolescence and early adulthood, and are frequently associated with considerable associated distress and functional decline. Our current diagnostic system lacks validity and therapeutic utility, particularly for the early stages of these mental disorders, when symptoms are still evolving and may have not yet stabilised sufficiently to fit familiar or traditional syndromal criteria. Furthermore, there is often difficulty in distinguishing transient developmental or normative changes from the early symptoms of persistent and disabling mental illness. These factors point to the need for reform of our current diagnostic systems. The clinical staging model seeks to define the extent of progression of a disorder at a particular point in time and aims to differentiate early, milder clinical phenomena from those that accompany illness progression and chronicity. The staging framework allows clinicians to select treatments relevant to earlier stages of an illness, and to evaluate their effectiveness in preventing progression and producing remission or return to milder or earlier stages of disorder. For staging to be a valid approach, interventions in the early stages need to shown to be not only more effective but also safer than treatments delivered later in the course of illness. Staging may also allow a more efficient integration of our rapidly expanding knowledge of the biological, social and psychological vulnerability factors involved in development of mental illness into what may ultimately resemble a clinicopathological staging model.

Does disturbance of self underlie social cognition deficits in schizophrenia and other psychotic disorders?

AIM

Although the different approaches to psychosis research have made significant advances in their own fields, integration between the approaches is often lacking. This paper attempts to integrate a strand of cognitive research in psychotic disorders (specifically, social cognition research) with phenomenological accounts of schizophrenia and other psychotic disorders.

METHOD

The paper is a critical investigation of phenomenological models of disturbed selfhood in schizophrenia in relation to cognitive theories of social cognition in psychotic disorders.

RESULTS

We argue that disturbance of the basic sense of self, as articulated in the phenomenological literature, may underlie the social cognition difficulties present in psychotic disorders. This argument is based on phenomenological thinking about self-presence ('ipseity') being the primary or most basic ground for the intentionality of consciousness - that is, the directedness of consciousness towards others and the world. A disruption in this basic ground of conscious life has a reverberating effect through other areas of cognitive and social functioning. We propose three routes whereby self-disturbance may compromise social cognition, including dissimilarity, disruption of lived body and disturbed mental coherence.

CONCLUSIONS

If this model is supported, then social cognition difficulties may be thought of as a secondary index or marker of the more primary disturbance of self in psychotic disorders. Further empirical work examining the relationship between cognitive and phenomenological variables may be of value in identifying risk markers for psychosis onset, thus contributing to early intervention efforts, as well as in clarifying the essential psychopathological features of schizophrenia and other psychotic disorders.

Nosological status and definition of schizophrenia: Some considerations for DSM-V and ICD-11

OBJECTIVE

Although dementia praecox or schizophrenia has been considered a unique disease entity for the past century, its definitions and boundaries have varied over this period. In this article, we examine the changing conceptualization of schizophrenia over the past 100 years and make some recommendations with regards to its definition in DSM-V and ICD-11.

METHODS

We summarize clinical features of schizophrenia in terms of symptomatology, course, and outcome. We examine factors that lead to changing definitions of a disorder such as schizophrenia, with specific reference to the evolution of its definition from DSM-1 (American Psychiatric Association, Washington, DC, 1952) to the current DSM-IV-TR.

RESULTS

Efforts to elucidate the etiology and pathophysiology of schizophrenia have been hampered by its imprecise definition and continuing transformations in its conceptualization. The definition of schizophrenia, at any given time, has been influenced by available diagnostic tools and treatments, other clinical considerations, extant knowledge and scientific paradigms. It is now clear that schizophrenia does not represent a single disease with a unitary etiology or pathogenetic process. Despite limitations in the concept, however, alternative approaches thus far have been unsuccessful in better defining the syndrome of schizophrenia or its component entities.

CONCLUSIONS

Whereas changing definitions of schizophrenia might impede research into its nature and development of more effective treatments, only a better understanding of schizophrenia can lead to its more precise definition. We consider the implications of our observations for DSM-V and ICD-11 definitions of schizophrenia and summarize some emerging preliminary recommendations.

Recent developments in philosophy of psychopathology

PURPOSE OF REVIEW

To survey recent developments in the English-language philosophy of psychopathology.

RECENT FINDINGS

First, we present books - by Gallagher and Zahavi (2008) and by Thompson (2007) -that integrate phenomenology with cognitive science and neuroscience. This is followed by discussion of critical assessments of the DSM-III operational legacy and practical consequences recently offered by various psychiatrists, including Andreasen, Mullen,and Maj. These very bleak assessments are considered in light of certain new trends in explanatory models of psychiatry and associated metaphysical concerns. Finally, we concentrate on the phenomenological approach to schizophrenia, enjoying a renaissance in psychiatric literature. We emphasize the recent work on the issue of self disorders as a core aspect of psychopathology of schizophrenia and criticize the accuracy of a recent survey (published in this journal) of phenomenological approaches to schizophrenia, thereby rectifying important misunderstandings.

SUMMARY

The review emphasizes the fundamental importance of philosophy of psychopathology in clarifying concepts, highlighting epistemological problems, and helping to provide adequate distinctions at the phenomenological level for use in empirical research.

Toward defining schizophrenia as a more useful clinical concept

Delineating schizophrenia remains elusive despite considerable interest and study for more than a century. During this time, a variety of terms and defining features have been ascribed to the construct. The predominant contemporary construct, for which substantial limitations persist, has changed little in the past 30 years. With the approaching arrival of the DSM-V, interest in the nosology of schizophrenia has rebounded. Recent publications have focused principally on the following: integrating dimensional approaches to diagnosis, subtypes of schizophrenia, endophenotypes, and identifying those at early risk as part of a staging process. Some have even suggested replacing the term. Although an etiopathic diagnosis remains out of reach, contemporary research is marching down several distinct paths toward defining schizophrenia as a construct of greater clinical utility.

The diagnostic status of first-rank symptoms

OBJECTIVE

In the International Statistical Classification of Diseases, Tenth Revision(ICD-10) and Diagnostic and Statistical Manual of Mental Disorder, Third and Fourth Edition(DSM-III-IV), the presence of one of Schneider "first-rank symptoms" (FRS) is symptomatically sufficient for the schizophrenia diagnosis. Yet, it has been claimed that FRS may also be found in the nonschizophrenic conditions, and therefore, they are not specific or diagnostic for schizophrenia. This review was made to clarify the issue of diagnostic specificity.

METHODS

(1) A critical review of FRS studies published in English between 1970 and 2005. (2) A highlight of the 5 most frequently cited studies identified in the Web of Science. (3) Theoretical implications of the epistemological issues of FRS.

RESULTS

The reviewed studies do not allow for either a reconfirmation or a rejection of Schneider's claims about FRS. The sources of disagreement between the studies are (1) including or excluding acute patients with potential degradation of consciousness; (2) assessing or not the phenomenological context; (3) assessing patients in different stages of their illness evolution; and (4) differential emphasis on mood symptoms and history of psychiatric symptoms.

CONCLUSION

Both DSM-IV and ICD-10 emphasize FRS to a degree that is not supported by the empirical evidence. Until the status of FRS is clarified in depth, we suggest that the FRS, as these are currently defined, should be de-emphasized in the next revisions of our diagnostic systems. Future studies aiming at validation of FRS as diagnostic features need to apply a phenomenological perspective and include a homogenous group of patients across a wide spectrum of diagnoses.

Biological, life course, and cross-cultural studies all point toward the value of dimensional and developmental ratings in the classification of psychosis

The diagnostic criteria for schizophrenia in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) are based on the premise that it is a discrete illness entity, in particular, distinct from the affective psychoses. This assumption has persisted for more than a century, even though patients with a diagnosis of schizophrenia show a wide diversity of symptoms and outcomes, and no biological or psychological feature has been found to be pathognomonic of the disorder. However, there has been sustained, and indeed growing, criticism of the concept. For example, writing about the diagnosis of schizophrenia more than a decade ago,2 one of Britain's most sophisticated nosological experts, Ian Brockington, enjoined "It is important to loosen the grip which the concept of 'schizophrenia' has on the minds of psychiatrists. Schizophrenia is an idea whose very essence is equivocal, a nosological category without natural boundaries, a barren hypothesis. Such a blurred concept is 'not a valid object of scientific enquiry'."3 Should Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition(DSM-V), persist with the neo-Kraepelinian concept of schizophrenia with all its defects, or should it deconstruct psychosis into its component dimensions? In this article, we will address the question by considering 2 main themes, firstly, the role of culture and ethnicity in the diagnosis of psychosis, and secondly, a life course approach to understanding psychosis. We will then discuss whether more progress would be achieved in DSM-V by abandoning the familiar categorical system and instead moving to a dimensional system which rates both developmental impairment and symptom factor scores. However, we will begin by briefly reviewing the recent history of the classification of the psychoses.