Principal-component analyses of PANSS and SANS-SAPS in schizophrenia: their stability in an acute phase

COSMIN systematic review and meta-analysis of the measurement properties of the Positive and Negative Syndrome Scale (PANSS)

Background

The Positive and Negative Syndrome Scale (PANSS) is the most widely used tool for assessing the symptoms of schizophrenia. Despite its widespread use, the psychometric properties of the PANSS have not been systematically reviewed. This study fills that gap in the scientific literature.

Methods

We utilized the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guideline for systematic reviews and meta-analytical procedures to assess the psychometric properties of the PANSS in its original three-subscale form as well as the quality level of the evidence available. On this basis we formulated recommendations for future research and use. A study protocol was registered under 10.17605/OSF.IO/5EGMD. The search period was until February 21, 2024.

Findings

We included 119 publications. According to COSMIN, the PANSS demonstrated sufficient reliability, construct validity, and responsiveness; but had significant shortcomings in content validity and structural validity. The original three-factor model showed poor structural validity, leading to its COSMIN classification as "not recommendable". The subscales showed overall acceptable measurement properties. However, the lack of structural validity of the three-subscale model renders its subscales less useful. Moreover, the PANSS negative subscale does not cover all domains of the National Institute of Mental Health consensus. Due to the length of the instrument (30-50 min), it is barely useable in clinical practice.

Interpretation

Although the PANSS is the standard scale for schizophrenia symptom severity, its shortcomings regarding fundamental psychometric domains and practical applicability warrant the development of new scales for which appropriate methods should be applied from the start.

Funding

There was no specific funding source for this research.

COSMIN review of the PANSS Marder factor solution and other factor models in people with schizophrenia

The Positive and Negative Syndrome Scale (PANSS) is widely used to assess schizophrenia symptoms. Initially designed with three subscales, Marder et al.´s 5-factor-Model (M5M) first proposed in 1997 has been frequently used in treatment trials, but it has never been systematically reviewed for its measurement properties. We utilized the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guideline for systematic reviews and meta-analytical procedures to assess the psychometric properties of the M5M-PANSS. COSMIN comprises several steps: literature search, risk-of-bias assessments, assessing the updated criteria for good measurement properties, feasibility aspects and grading the quality of the evidence. We further assessed the goodness of fit of other PANSS factor models. We included 95 publications. The M5M-PANSS showed good construct validity, but "insufficient" structural validity. Evidence of other COSMIN domains is largely lacking. Among the multiple (73) factor solutions examined with confirmatory methods, several other 5-factor solutions had better model fit. According to COSMIN rules the M5M should not be recommended for use. Other five-factor models such as the one proposed by Wallwork et al.1 warrant further evaluation. Nevertheless, the factor composition of the M5M and these other models was relatively similar, so previously published results should not be disregarded.

Meta-analysis of the factor structure of the Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS)

INTRODUCTION

The SAPS and SANS was designed to measure two broad factors, but the majority of factor analyses conducted have found substantially more dimensions. To investigate their structure a meta-analysis was conducted of SAPS and SANS factor analysis.

METHOD

A total of 42 articles reporting 55 factor analyses were retrieved from database searches (PubMed, PsychINFO) supplemented by searches of references. Reproduced correlations were calculated from retrieved factor analyses and 3 separate meta-analyses were conducted.

RESULTS

The meta-analysis of the SAPS SANS global ratings (k = 34; n = 5219) yielded a 3-factor solution including Positive Symptoms (Hallucinations and Delusions), Negative Symptoms (Affective Flattening, Alogia, Avolition/Apathy, Anhedonia/Asociality and Attentional Impairment), and Disorganization (Positive Formal Thought Disorder and Bizarre Behavior). The item analysis of the SAPS SANS combined (k = 11; n = 3146) found 4 factors, with the Negative Symptoms splitting into Affective Flattening/Alogia and Avolition/Asociality as main difference. The SANS only item analysis (k = 10; n = 2073) identified 3 factors, Affective Flattening, Avolition/Asociality, and Alogia/Inattentiveness. Importantly, our data suggests that the items Inappropriate Affect and Poverty of Content of Speech should be moved from Negative Symptoms to the Disorganization factor. Attentional Impairment shows the highest loading on Negative Symptoms but its inclusion under this dimension is conceptually unclear and it may be better considered as a non-specific domain.

CONCLUSIONS

The three factor structure of Positive Symptoms, Negative Symptoms and Disorganization accounted for most of the data. The SAPS SANS global scales are generally valid, but suggestions for a conservative revision of SAPS SANS structure, including supplementary subscales, are presented.

Large-scale evaluation of the Positive and Negative Syndrome Scale (PANSS) symptom architecture in schizophrenia

Although the Positive and Negative Syndrome Scale (PANSS) is widely utilized in schizophrenia research, variability in specific item loading exist, hindering reproducibility and generalizability of findings across schizophrenia samples. We aim to establish a common PANSS factor structure from a large multi-ethnic sample and validate it against a meta-analysis of existing PANSS models. Schizophrenia participants (N = 3511) included in the current study were part of the Singapore Translational and Clinical Research Program (STCRP) and the Clinical Antipsychotic Trials for Intervention Effectiveness (CATIE). Exploratory Factor Analysis (EFA) was conducted to identify the factor structure of PANSS and validated with a meta-analysis (N = 16,171) of existing PANSS models. Temporal stability of the PANSS model and generalizability to individuals at ultra-high risk (UHR) of psychosis were evaluated. A five-factor solution best fit the PANSS data. These were the i) Positive, ii) Negative, iii) Cognitive/disorganization, iv) Depression/anxiety and v) Hostility factors. Convergence of PANSS symptom architecture between EFA model and meta-analysis was observed. Modest longitudinal reliability was observed. The schizophrenia derived PANSS factor model fit the UHR population, but not vice versa. We found that two other domains, Social Amotivation (SA) and Diminished Expression (DE), were nested within the negative symptoms factor. Here, we report one of the largest transethnic factorial structures of PANSS symptom domains (N = 19,682). Evidence reported here serves as crucial consolidation of a common PANSS structure that could aid in furthering our understanding of schizophrenia.

Social class and type of schizophrenia

Objective

Current and past research strongly indicates a high prevalence of schizophrenia in the lower class in the USA and other stratified societies. To date, no study has tested for a connection between type of schizophrenia and socioeconomic status (SES). We tested for an interrelationship between schizophrenic subtype, SES and race.

Methods

Positive and negative symptom scales were used to evaluate 436 schizophrenic patients at a state hospital in the USA. All patients were also diagnosed by DSM standards. Social class of origin was assessed by the Occupational Classification Distributions of the U.S. Bureau of the Census. Multivariate analysis was conducted with the likelihood ratio chi-square.

Results

We uncovered a distinct propensity for deficit schizophrenia to be elevated among the poor. The finding presents as a pure SES effect since the likelihood of deficit schizophrenia does not vary by race when social class is held constant.

Conclusion

The finding is potentially an important new insight into the epidemiology of schizophrenia. It offers a better understanding for poor outcome among lower class patients in stratified societies such as the United States. It is also consistent with longitudinal research by European investigators.

The component structure of the scales for the assessment of positive and negative symptoms in first-episode psychosis and its dependence on variations in analytic methods

A secondary analysis was undertaken on Scales for the Assessment of Positive and Negative Symptoms (SAPS/SANS) data from 345 first-episode psychosis (FEP) patients gathered in the West London FEP study. The purpose of this study was to determine: (i) the component structure of these measures in FEP (primary analyses), and (ii) the dependence of any findings in these primary analyses on variations in analytic methods. Symptom ratings were exposed to data reduction methods and the effects of the following manipulations ascertained: (i) level of analysis (individual symptom vs. global symptom severity ratings), (ii) extraction method (principal component vs. exploratory factor analysis) and (iii) retention method (scree test vs. Kaiser criterion). Whilst global ratings level analysis rendered the classic triad of psychotic syndromes (positive, negative and disorganisation), symptom level analyses revealed a hierarchical structure, with 11 first-order components subsumed by three second-order components, which also mapped on to this syndrome triad. These results were robust across data reduction but not component retention methods, suggesting that discrepancies in the literature regarding the component structure of the SAPS/SANS partly reflect the level of analysis and component retention method used. Further, they support a hierarchical symptom model, the implications of which are discussed.

Factor structure of the positive and negative syndrome scale (PANSS) in people at ultra high risk (UHR) for psychosis

INTRODUCTION

The Positive and Negative Syndrome Scale (PANSS), a comprehensive psychopathology assessment scale used in the evaluation of psychopathology in schizophrenia, is also often used in the Ultra-High-Risk (UHR) population. This paper examined the dimensional structure of the PANSS in a UHR sample.

METHODS

A total of 168 individuals assessed to be at UHR for psychosis on the Comprehensive Assessment of At-Risk Mental States (CAARMS) were evaluated on the PANSS, Calgary Depression Scale for Schizophrenia (CDSS), Beck Anxiety Inventory (BAI), Brief Assessment of Cognition in Schizophrenia (BACS), and Global Assessment of Functioning (GAF). Exploratory factor analysis (EFA) of the PANSS was performed to identify the factorial structure. Convergent validity was explored with the CAARMS, CDSS, BAI and BACS.

RESULTS

EFA of the PANSS yielded five symptom factors - Positive, Negative, Cognition/Disorganization, Anxiety/Depression, and Hostility. This 5-factor solution showed good convergent validity with the CAARMS composite score, CDSS, BAI, and BACS. Positive, Negative and Anxiety/Depression factors were associated with functioning.

CONCLUSION

The reported PANSS factor structure may serve to improve the understanding and measurement of clinical symptom dimensions manifested in people with UHR for future research and clinical setting.

Symptom dimensions and subgroups in childhood-onset schizophrenia

OBJECTIVE

This study investigated symptom dimensions and subgroups in the National Institute of Mental Health (NIMH) childhood-onset schizophrenia (COS) cohort and their similarities to adult-onset schizophrenia (AOS) literature.

METHOD

Scores from the Scales for the Assessment of Positive and Negative Symptoms (SAPS & SANS) from 125 COS patients were assessed for fit with previously established symptom dimensions from AOS literature using confirmatory factor analysis (CFA). K-means cluster analysis of each individual's scores on the best fitting set of dimensions was used to form patient clusters, which were then compared using demographic and clinical data.

RESULTS

CFA showed the SAPS & SANS data was well suited to a 2-dimension solution, including positive and negative dimensions, out of five well established models. Cluster analysis identified three patient groups characterized by different dimension scores: (1) low scores on both dimensions, (2) high negative, low positive scores, and (3) high scores on both dimensions. These groups had different Full scale IQ, Children's Global Assessment Scale (CGAS) scores, ages of onset, and prevalence of some co-morbid behavior disorders (all p<3.57E-03).

CONCLUSION

Our analysis found distinct symptom-based subgroups within the NIMH COS cohort using an established AOS symptom structure. These findings confirm the heterogeneity of COS and were generally consistent with AOS literature.

Combined serum levels of multiple proteins in tPA-BDNF pathway may aid the diagnosis of five mental disorders

Mental disorders are severe, disabling conditions with unknown etiology and are commonly misdiagnosed when clinical symptomology criteria are solely used. Our previous work indicated that combination of serum levels of multiple proteins in tissue plasminogen activator (tPA)-brain-derived neurotrophic factor (BDNF) pathway improved accuracy of diagnosis of major depressive disorder (MDD). Here, we measured serum levels of tPA, plasminogen activator inhibitor-1 (PAI-1), BDNF, precursor-BDNF (proBDNF), tropomyosin-related kinase B (TrkB) and neurotrophin receptor p75 (p75NTR) in patients with paranoid schizophrenia (SZ, n = 34), MDD (n = 30), bipolar mania (BM, n = 30), bipolar depression (BD, n = 22), panic disorder (PD, n = 30), and healthy controls (HCs, n = 30) by Enzyme-linked immunosorbent assay kits. We used receiver operating characteristic (ROC) curve to analyze diagnostic potential of these proteins. We found, compared with HCs, that serum tPA and proBDNF were lower in SZ, BM and BD; TrkB was lower in SZ and BD; and p75NTR was declined in SZ and BM. ROC analysis showed that combined serum level of tPA, PAI-1, BDNF, proBDNF, TrkB and p75NTR was better than any single protein in accuracy of diagnosis and differentiation, suggesting that the combination of multiple serum proteins levels in tPA-BDNF pathway may have a potential for a diagnostic panel in mental disorders.

A cross-national factor analytic comparison of three models of PANSS symptoms in schizophrenia

The 30-item Positive and Negative Syndrome Scale (PANSS) is used worldwide in the assessment of symptom severity in schizophrenia. The present study uses confirmatory factor analysis (CFA) to compare three different factorial models and to evaluate the best-fitting representation of schizophrenia symptom structure on the PANSS across four samples of patients diagnosed with schizophrenia from the US (the CATIE schizophrenia trial), São Paulo, Brazil, and from Beijing and Changsha, China. We examine the goodness of fit of several previously proposed models. The traditional trifactorial model for the PANSS and two five-factor models were evaluated using absolute and incremental indices. Single group CFA found that the five-factor model proposed by NIMH researchers based on an extensive literature review demonstrates the best fit in each of the four samples. This model used 20 of the 30 PANSS items grouped into five factors: positive, negative, disorganized, excited, and depressed symptoms. Subgroups defined by age, gender, nationality, hospitalization status, and severity of illness also did not differ in overall symptom structure as assessed by several standard indices. Our findings suggest that the five factor NIMH model showed the best representation among all four samples from different countries and potentially contrasting cultures.

Symptom structure and severity: a comparison of responses to the positive and negative syndrome scale (PANSS) between patients with PTSD or schizophrenia

OBJECTIVES

To describe and compare the structure and relative severity of symptoms in clinical trial patients diagnosed with Post Traumatic Stress Disorder (PTSD) or schizophrenia using the Positive and Negative Syndrome Scale (PANSS), developed originally to evaluate symptoms of schizophrenia.

METHOD

This secondary data analysis used baseline PANSS symptom ratings (n=267) from a six-month multicenter randomized placebo-controlled trial of adjunctive risperidone in patients with chronic military-related PTSD. First, using a split-half design, Exploratory Factor Analysis (EFA) was employed to identify independent factors which were then compared to published factor structures for schizophrenia. Next, Confirmatory Factor Analysis (CFA) was applied to the second half of the sample to compare the results of the EFA and published factor structures. Finally, T-tests were used to compare the severity of factor scores between the PTSD sample and the baseline PANSS ratings from the Clinical Antipsychotic Trial for Intervention Effectiveness (CATIE) schizophrenia sample (n=1460).

RESULTS

EFA suggested five factors similar to those identified in a summary of 29 schizophrenia studies by Wallwork (Schizophrenia Research, 137:246-250). CFA showed that the five factor Wallwork model fit the data better than the EFA, although both had relatively high goodness of fit. T-tests showed that the PTSD sample had more severe symptoms on the Depressive factor, and the schizophrenia sample on the Positive, Negative, and Disorganized factors, with no significant difference on the Excited factor.

CONCLUSION

Veterans with PTSD had similar symptom structure to patients with schizophrenia on the PANSS, but were less symptomatic on psychosis-related factors and more symptomatic on depression. Dimensional symptom factors can be virtually the same across diagnoses.

Multilevel ordinal factor analysis of the positive and negative syndrome scale (PANSS)

Clinical assessments of the presence and severity of psychopathology are often collected by health care professionals in mental health services or clinical researchers trained to use semi-structured interviews. Clustering by interviewer or rater needs to be considered when performing psychometric analyses such as factor analysis or item response modelling as non-independence of observations arises in these situations. We apply more suitable multilevel methods to analyse ordinally scored Positive and Negative Syndrome Scale (PANSS) items. Our aim is to highlight the differences in results that occur when the data are analysed using a hierarchically sensitive approach rather than using a traditional (aggregated) analysis. Our sample (n = 507) consisted of patients diagnosed with schizophrenia who participated in a multi-centre randomized control clinical trial, the DIALOG study. Analyses reported and compared include an exploratory factor analysis as well as several recently published multifactor models re-estimated within a confirmatory analysis framework. Our results show that the fit of the model and the parsimony of the exploratory factor analysis (EFA) models indicated by the number of factors necessary to explain the inter-correlation among PANSS items improved significantly when data clustering is taken into account through multilevel analysis. Our modeling results support the pentagonal PANSS model first proposed by White et al. (1997). Copyright © 2014 John Wiley & Sons, Ltd.

Scale for the Assessment of Negative Symptoms structure in first episode psychosis

Previous studies in schizophrenia samples suggest negative symptoms can be categorized as expressivity or experiential. This study examines the structure of the Scale for the Assessment of Negative Symptoms (SANS) at two separate interviews in a first episode psychosis (FEP) sample. SANS structure was determined with principal components analysis in a schizophrenia spectrum (SSD, N=191) and non-schizophrenia spectrum (NSSD, N=246) sample at first presentation. Confirmatory factor analysis (CFA) was conducted in the entire FEP sample (N=197) at a follow-up assessment. A three factor model solution was extracted in both SSD and NSSD at first presentation. The three components, consisting of expressivity, experiential and alogia/inattention components, explained 26.1%, 16.6% and 13.6% of the variance respectively in SSD. In NSSD the same three components explained 24.2%, 17.9% and 13.1% of the variance respectively. CFA at follow-up showed similar model fit for both the original SANS five factor and for a three factor model solution. The results indicate that either a three or five factor SANS model solution may be appropriate in a psychosis sample inclusive of both SSD and NSSD. The findings also provide initial support for expressivity and experiential domain research in NSSD.

A new Integrated Negative Symptom structure of the Positive and Negative Syndrome Scale (PANSS) in schizophrenia using item response analysis

BACKGROUND

Debate persists with regard to how best to categorize the syndromal dimension of negative symptoms in schizophrenia. The aim was to first review published Principle Components Analysis (PCA) of the PANSS, and extract items most frequently included in the negative domain, and secondly, to examine the quality of items using Item Response Theory (IRT) to select items that best represent a measurable dimension (or dimensions) of negative symptoms.

METHODS

First, 22 factor analyses and PCA met were included. Second, using a large dataset (n=7187) of participants in clinical trials with chronic schizophrenia, we extracted items loading on one or more PCA. Third, items not loading with a value of ≥ 0.5, or loading on more than one component with values of ≥ 0.5 were discarded. Fourth, resulting items were included in a non-parametric IRT and retained based on Option Characteristic Curves (OCCs) and Item Characteristic Curves (ICCs).

RESULTS

15 items loaded on a negative domain in at least one study, with Emotional Withdrawal loading on all studies. Non-parametric IRT retained nine items as an Integrated Negative Factor: Emotional Withdrawal, Blunted Affect, Passive/Apathetic Social Withdrawal, Poor Rapport, Lack of Spontaneity/Conversation Flow, Active Social Avoidance, Disturbance of Volition, Stereotyped Thinking and Difficulty in Abstract Thinking.

CONCLUSIONS

This is the first study to use a psychometric IRT process to arrive at a set of negative symptom items. Future steps will include further examination of these nine items in terms of their stability, sensitivity to change, and correlations with functional and cognitive outcomes.

Two subdomains of negative symptoms in psychotic disorders: established and confirmed in two large cohorts

Negative symptoms of schizophrenia are normally grouped into a single category. However, the diversity of such symptoms suggests that they are actually made up of more than one dimension. The DSM-V proposes two negative symptom domains, namely expressive deficits and avolition/asociality. We investigated whether the negative symptoms do indeed have two dimensions. An exploratory factor analysis was carried out based on interviews with the PANSS (664 patients). We restricted our analysis to items that had been described as negative symptoms in previous factor analyses. The symptom structure was then tested for stability by performing a confirmatory factor analysis on PANSS interviews from a separate cohort (2172 patients). Exploratory factor analysis yielded a two-factor structure of negative symptoms. The first factor consisted of PANSS items Flat affect, Poor rapport, Lack of spontaneity, Mannerisms and posturing, Motor retardation, and Avolition. The second factor consisted of Emotional withdrawal, Passive/apathetic social withdrawal, and Active social avoidance. The first factor could be related to expressive deficits, reflecting a loss of initiative, and the second factor to social amotivation, related to community interaction. This factor structure supports the DSM-V classification and may be relevant for pathophysiology and treatment of schizophrenia and other psychotic disorders.

Cognition and the five-factor model of the positive and negative syndrome scale in schizophrenia

Different exploratory and confirmatory factorial analyses of the Positive and Negative Syndrome Scale (PANSS) have found a number of factors other than the original positive, negative, and general psychopathology. Based on a review of previous studies and using confirmatory factor analyses (CFA), Wallwork et al. (Schizophr Res 2012; 137: 246-250) have recently proposed a consensus five-factor structure of the PANSS. This solution includes a cognitive factor which could be a useful measure of cognition in schizophrenia. Our objectives were 1) to study the psychometric properties (factorial structure and reliability) of this consensus five-factor model of the PANSS, and 2) to study the relationship between executive performance assessed using the Wisconsin Card Sorting Test (WCST) and the proposed PANSS consensus cognitive factor (composed by items P2-N5-G11). This cross-sectional study included a final sample of 201 Spanish outpatients diagnosed with schizophrenia. For our first objective, CFA was performed and Cronbach's alphas of the five factors were calculated; for the second objective, sequential linear regression analyses were used. The results of the CFA showed acceptable fit indices (NNFI=0.94, CFI=0.95, RMSEA=0.08). Cronbach's alphas of the five factors were adequate. Regression analyses showed that this five-factor model of the PANSS explained more of the WCST variance than the classical three-factor model. Moreover, higher cognitive factor scores were associated with worse WCST performance. These results supporting its factorial structure and reliability provide robustness to this consensus PANSS five-factor model, and indicate some usefulness of the cognitive factor in the clinical assessment of schizophrenic patients.

Validated five-factor model of positive and negative syndrome scale for schizophrenia in Chinese population

The Positive and Negative Syndrome Scale (PANSS) is the most widely used instrument to assess the severity of symptoms of schizophrenia. Most studies have showed that PANSS measures five dimensions of symptomatology of schizophrenia. However, few studies have ever investigated the structure of PANSS in Chinese schizophrenia population. We recruited two large independent study samples including 903 and 942 Chinese schizophrenia patients and examined the underlying structure of PANSS. By building a confirmatory factor analysis (CFA) model based on the factor loadings of the exploratory factor analysis (EFA) and by testing the CFA model in an independent validation sample, we found that PANSS scores consisted of five factors, which were positive factor, negative factor, excitement factor, depression factor, and cognitive factor. The items loaded on these factors were similar to the consensus items published in previous studies except for PANSS items P2 conceptual disorganization, P5 grandiosity, N5 abstract thinking, and G11 poor attention. This difference might be due to the influence of culture on clinical presentation of schizophrenia. By elucidating the structure, symptoms of Chinese schizophrenia patients could possibly be deconstructed and investigated in future studies.

Searching for a consensus five-factor model of the Positive and Negative Syndrome Scale for schizophrenia

Although the developers of the Positive and Negative Syndrome Scale (PANSS) grouped items into three subscales, factor analyses indicate that a five-factor model better characterizes PANSS data. However, lack of consensus on which model to use limits the comparability of PANSS variables across studies. We counted "votes" from published factor analyses to derive consensus models. One of these combined superior fit in our Caucasian sample (n=458, CFI=.970), and in distinct Japanese sample (n=164, CFI=.964), relative to the original three-subscale model, with a sorting of items into factors that was highly consistent across the studies reviewed.

Effects of antipsychotic treatment on psychopathology and motor symptoms. A placebo-controlled study in healthy volunteers

RATIONALE

There is increased interest in elucidating the range of symptoms of schizophrenia and their response to treatment with medications. Particularly negative and cognitive symptoms are often resistant to the therapy with currently available antipsychotics. There are even similarities between negative symptoms in psychosis and the side effects of antidopaminergic antipsychotic drugs.

OBJECTIVES

The aim of this randomized, single-blinded, placebo-controlled study was to investigate the influence of a subchronic, prolonged neuroleptic-induced dopamine deficit on psychopathology and subjective well-being in healthy subjects.

METHODS

Seventy-two healthy volunteers without history of psychiatric diseases were included. A 7-day antidopaminergic intervention was provided with aripiprazole, haloperidol, and reserpine. For the clinical assessment, structured interviews and psychopathology and extrapyramidal symptom scales were used.

RESULTS

Seven out of 18 participants (38.9%) randomized to the haloperidol group terminated the study ahead of schedule. In the reserpine and the haloperidol group, significantly higher levels of negative and positive symptoms (PANSS scale) were documented. Depressive symptoms predominantly occurred in the reserpine group. Among all participants experiencing the antidopaminergic intervention, the subgroup with positive family history among first and second-generation relatives developed more pronounced depressive symptoms. Concerning extrapyramidal motor symptoms, the haloperidol group had significantly more severe manifestations than all three other groups.

CONCLUSION

Antidopaminergic modulation in healthy subjects induced substantial impairments in several domains of subjective well-being. In particular an association between hypodopaminergic states and depressive symptoms was observed which may be amplified by a genetic predisposition.

Patient subgroups of schizophrenia based on the Positive and Negative Syndrome Scale: composition and transition between acute and subsided disease states

The present study focuses on schizophrenia patient subgroups with specific symptom pattern using the Positive and Negative Syndrome Scale (PANSS). In this report, we intend to (1) provide a more appropriate analytic method for exploring the subgroups based on PANSS data, (2) validate identified subgroups with external variables, and (3) estimate probabilities of subgroup changes between 2 disease states. The analyzed data include 219 acute-state patients who had completed the PANSS within 1 week of index admission and 225 subsided-state patients who were living in the community and under family care. Regression extension of latent class analysis was performed. We found that acute schizophrenia can be classified into 4 subgroups--whole syndrome, whole syndrome without hostility, partial syndrome with negative symptoms, and partial syndrome with pure reality distortion--and that subsided schizophrenia can be classified into 3 subgroups--florid symptom, marked negative, and remitted. Patients of the whole syndrome, whole syndrome without hostility, partial syndrome with negative symptoms, and partial syndrome with pure reality distortion subgroups at the acute state were most likely to transit to the florid symptom (61%), florid symptom (48%), marked negative (42%), and remitted (56%) subgroups at the subsided state, respectively. Significant relationships of obtained subgroups with sociodemographic variables and neurocognitive variables were identified. These results of different subgroups will provide the background for facilitating current molecular, genetic, and neurobiological studies of schizophrenia.

Obstetrical complications, social class and type of schizophrenia

The emerging neurodevelopmental model posits that prenatal and perinatal factors can play an etiological role in schizophrenia. Consistently, the research on obstetrical complications (OCs) reports an association with the development of more severe schizophrenic symptoms. Low socioeconomic status (SES) has also been linked to both limited prenatal healthcare and to worse prognosis of schizophrenic symptoms. A large sample (n=437) of patients from a state hospital population in the U. S. was screened for study variables. A sequential analysis was conducted, first applying cross tabulations using the chi-square test, and then building separate logit models for poor and nonpoor patients. The cross tabulations indicated an association between OCs and negative symptoms for poor schizophrenic patients, but not for nonpoor patients. Multivariate logit models further supported this result. This is the first study to examine the interaction of OCs, schizophrenic symptomatology and SES of origin.

A unified approach to multi-item reliability

The reliability of multi-item scales has received a lot of attention in the psychometric literature, where a myriad of measures like the Cronbach's α or the Spearman-Brown formula have been proposed. Most of these measures, however, are based on very restrictive models that apply only to unidimensional instruments. In this article, we introduce two measures to quantify the reliability of multi-item scales based on a more general model. We show that they capture two different aspects of the reliability problem and satisfy a minimum set of intuitive properties. The relevance and complementary value of the measures is studied and earlier approaches are placed in a broader theoretical framework. Finally, we apply them to investigate the reliability of the Positive and Negative Syndrome Scale, a rating scale for the assessment of the severity of schizophrenia.

Causal model of insight and psychopathology based on the PANSS factors: 1-year cross-sectional and longitudinal revalidation

This study presents results of a 1-year follow-up investigation of the causal model of insight in schizophrenia using a subsample of acute patients starting or switching to amisulpride included in an earlier study. Our causal model of insight based on the Positive and Negative Syndrome Scale factors, with the positive, negative, and autistic preoccupation factors designated as the primary predictors, and the activation factor as a mediating variable of insight, was examined for fitness at the stabilized stage (8 week) and at the chronic stage (1 year) using the structural equation modeling method. Results showed that the intercorrelations among the factors and regression coefficients toward insight changed in their magnitudes, but the validity of our hypothesized model of insight was still confirmed for both the stages with nearly perfect goodness-of-fitness indices. The fitness of the model was also confirmed for the longitudinal changes in the scores of insight and psychopathology. An alternative model, which included the anxiety/depressive factor as a second mediating variable between insight and the positive and negative factors, was also found to be valid for both the stages. A post-hoc causal model with anxiety/depressive factor showed tentative evidence favoring anxiety/depressive variable predicting insight than the other way around.

Social class, family history and type of schizophrenia

To date, there are numerous studies supporting a genetic model of schizophrenia. There is a paucity of studies, however, screening for a connection between family history of serious mental illness and deficit vs. nondeficit schizophrenia. The aim of the present study was to explore the association between family history, deficit vs. nondeficit schizophrenia and socioeconomic status (SES) of family of origin. Patients (N=437) from a United States psychiatric hospital were separated into deficit vs. nondeficit presentation and bifurcated into poor vs. nonpoor SES. Family history data were utilized to classify patients into subgroups characterized by serious mental illness within immediate family, within extended family, or no evidence of mental illness. Statistical testing was conducted using logistic regression analysis. SES of family of origin was significantly associated with schizophrenic subtype independently of family history, sex and race; specifically, poverty raised the risk of deficit schizophrenia. Family history of mental illness showed no net association, and no statistical interaction with poverty, in predicting risk of deficit schizophrenia.

The negative syndrome as a dimension: factor analyses of PANSS in major depressive disorder and organic brain disease compared with negative syndrome structures found in the schizophrenia literature

OBJECTIVE

To explore the concept of the negative syndrome as a dimensional entity that exists in multiple primary diagnoses, and to compare the negative syndrome in nonschizophrenic disorders and schizophrenia.

BACKGROUND

Although initially considered specific to schizophrenia, the negative syndrome has subsequently been described in major depression, stroke, and dementia.

METHOD

We performed an exploratory factor analysis on Positive and Negative Symptom Scale scores of 82 subjects with major depressive disorder and 76 subjects with organic brain disease (dementia or stroke).

RESULTS

The examination of the resultant symptom clusters revealed that the structure of the negative syndrome in major depressive disorder and organic brain disease closely corresponded to that in schizophrenia literature.

CONCLUSIONS

The negative syndrome may be a nosologic entity, which remains fairly consistent across psychotic and nonpsychotic diagnostic categories. Confirmatory studies are merited to determine the degree and strength of the similarity in structure of the negative syndrome in psychotic, affective, and cognitive illness.

Schizophrenic subtype, seasonality of birth and social class: a preliminary analysis

OBJECTIVE

The neurodevelopmental model of schizophrenia includes the etiological impact of fetal brain stressors possibly connected with birth seasonality. Specification of social class of origin (SES) as a related risk factor remains unexamined as does type of schizophrenia as an outcome variable. The objective of this study was to test for an interconnection between SES, type of schizophrenia and seasonality of birth.

METHODS

Patients (N=436) from a United States psychiatric hospital were separated into deficit/non-deficit presentation and bifurcated into poor/non-poor SES. Birth seasonality was assessed by months hypothetically connected with winter-related trimesters of gestation.

RESULTS

Results showed that there is a significant difference (p=0.0411) in the monthly birth patterns of poor vs. non-poor patients and that the difference connects with the likelihood of deficit vs. non-deficit schizophrenia. Specifically, an elevated proportion of patients with deficit schizophrenia were born to impoverished women who likely conceived in January. Findings were confirmed by multiple levels of statistical assessment including log linear analysis.

CONCLUSION

The resultant model suggests the environmental location (lower SES) and timing (winter conception) of adult schizophrenia with poor outcome (deficit).

The evolution of symptoms in the early course of non-affective psychosis

Most previous studies investigating the factor structure of psychosis have focussed on chronic samples. First episode samples with longitudinal follow up are few. To investigate the stability and validity of symptom factors, a sample of 257 patients with DSM IV nonaffective psychoses were assessed using the PANSS during the acute first episode and at 3- and 18-month follow up. Exploratory factor analysis of the changes in PANSS item scores over time gave a five-factor solution. This was consistent with the solutions to factor analyses at the initial assessment and each of the follow-ups. However, there was progression over follow-up. Confirmatory factor analysis demonstrated that symptom ratings at 18-month follow-up fitted the models from existing research, in relatively chronic samples, better than the ratings at the initial assessment. A psychomotor poverty factor showed most stability over time and a positive symptom factor most change. Factors showed different associations with demographic and external variables, further supporting their validity.

Patterns of symptoms in neuroleptic-naive patients with schizophrenia and related psychotic disorders before and after treatment

A three-factor structure of schizophrenic symptoms has received considerable support, but there are no data on the factor structure of symptoms in neuroleptic-naive patients and how symptoms evolve after the inception of antipsychotic treatment. Seventy neuroleptic-naive patients with schizophrenia or related psychotic disorders were assessed with the Scales for the Assessment of Positive and Negative Symptoms before and after neuroleptic treatment. Ten global ratings of symptoms were subjected to factor analysis at the two time points and the factor solutions compared. A three-factor structure composed of psychotic, disorganization, and negative dimensions was found at the two assessment points. The negative and disorganization factors were highly correlated at each assessment and across assessments. While the symptom composition of the factors at the neuroleptic-naive assessment fitted that described in most previous studies, the composition of the negative and disorganization factors after neuroleptic treatment was somewhat different in that attention and inappropriate affect loaded on the negative factor instead of the disorganization factor. It is concluded that caution is warranted when using the three-factor model of schizophrenic symptoms as it may not be stable at different phases of the illness.

How many and which are the psychopathological dimensions in schizophrenia? Issues influencing their ascertainment

During the last two decades, much effort has been made to precisely characterize the symptom dimensions of schizophrenia. A number of dimensional models have been proposed, the most popular of which has been a three-dimensional model consisting of psychotic, negative and disorganizational symptoms. This model, however, has been criticized as too simplistic, and more complex models have been proposed, although to date there has been no consensus as to the number and nature of dimensions necessary to account for the whole range of schizophrenic symptoms. In the present paper, the authors review the main methodological issues which have led to the current confusion about the number of dimensions underlying schizophrenic psychopathology. Among the main issues influencing the delimitation of dimensions are: statistical procedures for determining the number of factors, phase of the illness, level of analysis of symptoms (i.e., symptoms or groups of symptoms), and measurement instrument used. Studies analyzing either a broad range of symptoms or particular symptoms at a finer level have produced a rather complex picture of schizophrenic dimensions. There is evidence supporting the existence of eight major dimensions of psychopathology: psychosis, disorganization, negative, mania, depression, excitement, catatonia and lack of insight. The dimensional structure of symptoms becomes even more complex if one considers that these big dimensions can be further divided into more elementary components. A hierarchical approach for organizing the complex dimensional structure of schizophrenic symptoms is proposed.

Stability of the five-factor structure of the Positive and Negative Syndrome Scale (PANSS)

The main objective of the study was to verify the stability of the five-factor (negative. positive, excitation, depression and cognitive) structure of the Positive and Negative Syndrome Scale (PANSS). The psychometric properties (validity and reliability) of the forced five-factor structure of the PANSS were explored in two different populations of schizophrenic patients: one in relapse and the other in the chronic phase of the disease. Three hundred and forty-two schizophrenic patients according to DSM-III-R criteria were involved. One hundred and eighteen (34.5%) patients were in relapse, and 224 (65.5%) were in the chronic phase. The forced five-factor principal-component analysis explained 64.3% of the total variance in the relapse patients and 62.1% in the chronic patients. The order of the factors was reversed for the depression and excitation factors in chronic patients compared with patients in relapse. The internal consistency of this five-factor structure was good (Cronbach's alpha >0.70) in the relapse and chronic patients, except for the cognitive factor. In conclusion. five dimensions (negative, positive, excitation, depression and cognition) are necessary to account for the various clinical aspects of schizophrenia described by PANSS in relapse and chronic schizophrenic patients.

Clozapine and negative symptoms. An open study

1. Clozapine, the first atypical antipsychotic, has demonstrated an efficacy in the treatment of resistant schizophrenia. But one of the major challenge in the treatment of schizophrenia remains the lack of efficacy of antipsychotics on negative symptoms of schizophrenia. 2. The authors studied the efficacy of clozapine in an open study in a population of 51 patients, who met the DSM IV criteria for schizophrenia. Using the positive and negative symptom scale (P.A.N.S.S.), and the Extra Pyramidal Symptoms Rating Scale (E.S.R.S.), we try to identify the specificity of the action of clozapine on the different symptomatic dimensions of schizophrenia. 3. The efficacy of clozapine was clinically significant on the negative symptomatology but was delayed compared to the efficacy on the other dimensions of symptomatology evaluated using the PANSS. 4. Nine patients, were considered as deficit patients; in this sample clozapine also demonstrated a significant efficacy on negative symptoms. The efficacy of clozapine did not seem to be a consequence of the better neurological tolerance of this antipsychotic evaluated with ESRS.

An exploration of the psychometric properties of the French version of the Positive and Negative Syndrome Scale

The psychometric properties of the French version of the Positive and Negative Syndrome Scale (PANSS) were studied in a population of 85 patients diagnosed with schizophrenia in accordance with Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria. The results of the study of the properties (internal consistency and principal-component analysis) of the initial structure with 3 scales (positive, negative, and general psychopathology) led us to investigate other factorial structures. We thus isolated a 5-factor structure (negative, hostility, positive, disorganization, and anxiety), explaining 54.7% of the total variance. The internal consistency of the 5 factors isolated was good (0.79, negative factor; 0.71, hostility factor; 0.77, positive factor; 0.66, disorganization factor; and 0.61, anxiety factor). The 3-subscale structure of the PANSS is discussed.

Validity and reliability of the French-language version of the Positive and Negative Syndrome Scale (PANSS)

OBJECTIVE

The main objective of this study was to evaluate the psychometric properties of the French-language version of the Positive and Negative Syndrome Scale (PANSS).

METHOD

The validity and reliability of the PANSS were studied in a population of 342 patients diagnosed as schizophrenic according to DSM-III-R criteria.

RESULTS

The study of the internal consistency and principal-component analysis of the initial structure with three subscales (positive, negative and general psychopathology) led us to investigate other factorial structures. We isolated a 5-factor structure (negative, positive, hostility, disorganization and anxiety/depression) explaining 57.5% of the total variance. The internal consistency of the 5 factors isolated was good (0.87 for the negative factor, 0.82 for the positive factor, 0.78 for the hostility factor, 0.71 for the disorganization factor and 0.68 for the anxiety/depression factor, respectively). The validity study on the external criteria confirmed the relationship between the negative and anxiety/depression factors and the extrapyramidal symptoms.

CONCLUSION

The stability of the PANSS factorial warrants discussion.

Factorial structure of the Positive and Negative Syndrome Scale (PANSS): a forced five-dimensional factor analysis

We conducted a study on 205 schizophrenic patients in order to explore the factorial structure of the Positive and Negative Syndrome Scale (PANSS). We first documented the validity and reliability of the five-dimensional structure of the PANSS, initially derived from the work of Kay and Sevy and completed by Lindenmayer et al. Some items (stereotyped thinking, mannerisms and posturing, poor attention, lack of judgement, disturbance of volition, and preoccupation) appeared to contribute little to the constitution of the dimensions initially described by Kay and Sevy. Those items were not taken into account in the forced five-dimensional factor analysis. We therefore investigated further the psychometric properties of the PANSS using only the retained items. The validity and reliability of this new five-dimensional structure are discussed.

Structure of schizophrenic symptomatology and its changes over time: prospective factor-analytical study

A representative sample of 156 new schizophrenic patients (DSM-III) were examined at the time of their first treatment contact for psychosis, and re-examined 2 and 5 years thereafter. The symptom variables, assessed by the Comprehensive Psychopathological Rating Scale (CPRS), were factored and compared with each other. The following major dimensions were found: (i) a fairly stable negative dimension with effective and speech impoverishment and withdrawal; (ii) a delusional dimension; (iii) hallucinatory dimensions; (iv) a disorganization dimension; and (v) a depressive dimension with unreal experiences. The negative dimension was more prevalent in unmarried patients. Neither the two-syndrome model of negative and positive symptoms nor the three-syndrome model of psychomotor poverty, disorganization and reality distortion proved to be satisfactory. In a representative sample of schizophrenic patients, the syndrome structure described by symptom dimensions appears to be more complex and varies considerably according to the duration of the illness.