A rasch model to test the cross-cultural validity in the positive and negative syndrome scale (PANSS) across six geo-cultural groups

Conducting cross-cultural, multi-lingual or multi-country scale development and validation in health care research: A 10-step framework based on a scoping review

Background

Valid, reliable and cross-cultural equivalent scales and measurement instruments that enable comparisons across diverse populations in different countries are important for global health research and practice. We developed a 10-step framework through a scoping review of the common strategies and techniques used for scale development and validation in a cross-cultural, multi-lingual, or multi-country setting, especially in health care research.

Methods

We searched MEDLINE, Embase, and PsycINFO for peer-reviewed studies that collected data from two or more countries or in two or more languages at any stages of scale development or validation and published between 2010-22. We categorised the techniques into three commonly used scale development and validation stages (item generation, scale development, and scale evaluation) as well as during the translation stage. We described the most commonly used techniques at each stage.

Results

We identified 141 studies that were included in the analysis. We summarised 14 common techniques and strategies, including focus groups or interviews with diverse target populations, and involvement of measurement experts and linguists for item content validity expert panel at the item generation stage; back-and-forth translation, collaborative team approach for the translation stage; cognitive interviews and different recruitment strategies and incentives in different settings for scale development stage; and three approaches for measurement invariance (multigroup confirmatory factor analysis, differential item functioning and multiple indicator multiple causes) for scale evaluation stage.

Conclusions

We provided a 10-step framework for cross-cultural, multi-lingual or multi-country scale development and validation based on these techniques and strategies. More research and synthesis are needed to make scale development more culturally competent and enable scale application to better meet local health and development needs.

Digital phenotyping correlates of mobile cognitive measures in schizophrenia: A multisite global mental health feasibility trial

Traditional cognitive assessments in schizophrenia are time-consuming and necessitate specialized training, making routine evaluation challenging. To overcome these limitations, this study investigates the feasibility and advantages of utilizing smartphone-based assessments to capture both cognitive functioning and digital phenotyping data and compare these results to gold standard measures. We conducted a secondary analysis of data from 76 individuals with schizophrenia, who were recruited across three sites (one in Boston, two in India) was conducted. The open-source mindLAMP smartphone app captured digital phenotyping data and Trails A/B assessments of attention / memory for up to 12 months. The smartphone-cognitive tasks exhibited potential for normal distribution and these scores showed small but significant correlations with the results from the Brief Assessment of Cognition in Schizophrenia, especially the digital span and symbol coding tasks (r2 = 0.21). A small but significant correlation (r2 = 0.29) between smartphone-derived cognitive scores and health-related behaviors such as sleep duration patterns was observed. Smartphone-based cognitive assessments show promise as cross-cultural tools that can capture relevant data on momentary states among individuals with schizophrenia. Cognitive results related to sleep suggest functional applications to digital phenotyping data, and the potential of this multimodal data approach in research.

Evaluating a smartphone-based symptom self-monitoring app for psychosis in China (YouXin): A non-randomised validity and feasibility study with a mixed-methods design

Background

Psychosis causes a significant burden globally, including in China, where limited mental health resources hinder access to care. Smartphone-based remote monitoring offers a promising solution. This study aimed to assess the validity, feasibility, acceptability, and safety of a symptom self-monitoring smartphone app, YouXin, for people with psychosis in China.

Methods

A pre-registered non-randomised validity and feasibility study with a mixed-methods design. Participants with psychosis were recruited from a major tertiary psychiatric hospital in Beijing, China. Participants utilised the YouXin app to self-monitor psychosis and mood symptoms for four weeks. Feasibility outcomes were recruitment, retention and outcome measures completeness. Active symptom monitoring (ASM) validity was tested against corresponding clinical assessments (PANSS and CDS) using Spearman correlation. Ten participants completed qualitative interviews at study end to explore acceptability of the app and trial procedures.

Results

Feasibility parameters were met. The target recruitment sample of 40 participants was met, with 82.5% completing outcome measures, 60% achieving acceptable ASM engagement (completing >33% of all prompts), and 33% recording sufficient passive monitoring data to extract mobility indicators. Five ASM domains (hallucinations, suspiciousness, guilt feelings, delusions, grandiosity) achieved moderate correlation with clinical assessment. Both quantitative and qualitative evaluation showed high acceptability of YouXin. Clinical measurements indicated no symptom and functional deterioration. No adverse events were reported, suggesting YouXin is safe to use in this clinical population.

Conclusions

The trial feasibility, acceptability and safety parameters were met and a powered efficacy study is indicated. However, refinements are needed to improve ASM validity and increase passive monitoring data completeness.

The Relationship Between Level of Education, Cognitive Function and Medication Adherence in Patients with Schizophrenia

Purpose

Several studies have explored the relationship between level of education and medication adherence, as well as the relationship between level of education and cognitive function. However, there have been few studies on the relationships between level of education, cognitive function, and medication adherence. This study aimed to explore whether cognitive function has a mediating effect between level of education and medication adherence in patients with schizophrenia.

Patients and Methods

A total of 329 participants were included in this study. Cognitive function was assessed using the Brief Assessment of Cognition in Schizophrenia, and medication adherence using the Medication Adherence Questionnaire. The relationships between the clinical factors and cognitive function that contributed to medication adherence were tested through multivariable linear regression analysis. The mediating effect of medication adherence was tested using the bootstrapping approach with the PROCESS macro.

Results

Family history, insight and executive function were associated with medication adherence in individuals with schizophrenia, and executive function had a mediating effect between level of education and medication adherence.

Conclusion

Adopting specific education programs that promote cognitive development as well as actively intervening in executive function might be conducive to improve medication adherence in patients with schizophrenia.

Voice Patterns as Markers of Schizophrenia: Building a Cumulative Generalizable Approach Via a Cross-Linguistic and Meta-analysis Based Investigation

BACKGROUND AND HYPOTHESIS

Voice atypicalities are potential markers of clinical features of schizophrenia (eg, negative symptoms). A recent meta-analysis identified an acoustic profile associated with schizophrenia (reduced pitch variability and increased pauses), but also highlighted shortcomings in the field: small sample sizes, little attention to the heterogeneity of the disorder, and to generalizing findings to diverse samples and languages.

STUDY DESIGN

We provide a critical cumulative approach to vocal atypicalities in schizophrenia, where we conceptually and statistically build on previous studies. We aim at identifying a cross-linguistically reliable acoustic profile of schizophrenia and assessing sources of heterogeneity (symptomatology, pharmacotherapy, clinical and social characteristics). We relied on previous meta-analysis to build and analyze a large cross-linguistic dataset of audio recordings of 231 patients with schizophrenia and 238 matched controls (>4000 recordings in Danish, German, Mandarin and Japanese). We used multilevel Bayesian modeling, contrasting meta-analytically informed and skeptical inferences.

STUDY RESULTS

We found only a minimal generalizable acoustic profile of schizophrenia (reduced pitch variability), while duration atypicalities replicated only in some languages. We identified reliable associations between acoustic profile and individual differences in clinical ratings of negative symptoms, medication, age and gender. However, these associations vary across languages.

CONCLUSIONS

The findings indicate that a strong cross-linguistically reliable acoustic profile of schizophrenia is unlikely. Rather, if we are to devise effective clinical applications able to target different ranges of patients, we need first to establish larger and more diverse cross-linguistic datasets, focus on individual differences, and build self-critical cumulative approaches.

Differential Treatment Responses in Pakistani Schizophrenia Samples: Correlation with Sociodemographic Parameters, Drug Addiction, Attitude to the Treatment and Antipsychotic Agents

Schizophrenia patients demonstrate variations in response to different therapies that are currently being used for the treatment of disorders, such as augmentation therapy (ECT or mood stabilizer) and combination therapy (with antipsychotics). These therapies are also used to treat schizophrenia patients in Pakistan; however, patients show poor overall response. Therefore, this study was conducted to investigate the association between the patients’ response to treatment and the use of antipsychotic agents, with variability in overall response, within different groups of patients. Methods: We conducted a retrospective study that included schizophrenia subjects (N = 200) belonging to different age groups, ethnicities, and regions from different outpatient and inpatient departments in psychiatric institutes located in different cities of Pakistan. These patients were assessed for their response to treatment therapies and categorized into four groups (non-responders (N-R), slow response (S-R), patients with relapse, and completely recovered patients (C-R)) according to their responses. Results: The final analysis included 200 subjects, of which 73.5% were males. Mean age was 34 ± 10 years. Percentage of N-R was 5%, S-R was 42%, patients with relapse were 24%, and C-R was 1.5%. The generalized linear regression model shows a significant association between medication response and age (p = 0.0231), age of onset (p = 0.0086), gender (p = 0.005), and marital status (p = 0.00169). Variability within the medication responses was a result of the treatment regime followed. Antipsychotic agents were significantly associated with the treatment response (p = 0.00258, F = 4.981) of the patients. Significant variation was also observed in the treatment response (p = 0.00128) of the patients that were given augmentation therapy as well as combination therapy. Conclusion: The data suggests proper monitoring of patients’ behavior in response to treatment therapies to implement tailored interventions. Despite several genetic studies supporting the heritability of schizophrenia, an insignificant association between characteristic features and family history might have been due to the limited sample size, suggesting collaborative work with massive sample sizes.

Quality of Life in Patients with Chronic Psychotic Disorders: A Practical Model for Interventions in Romanian Mental Health Centers

Background and Objectives: Current psychiatric care is increasingly focusing on patients' quality of life (QoL). Research is still trying to determine the main factors which influence QoL. The present study aims to assess the QoL of patients with chronic psychotic-spectrum disorders, as well as its relation to symptomatology, functionality, adaptive behavior, and perceived level of recovery. Materials and Methods: The study included a sample of 78 patients with chronic psychosis. Symptomatology and illness severity were assessed with the Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impression Scale-Severity (CGI-S) scales, respectively. The Global Assessment of Functioning Scale (GAFS) and the Adaptive Behavior Assessment System II (ABAS-II)-Adult Form were used for the assessment of patients' functionality, and the Quality-of-Life Inventory (QOLI) scale was applied for the evaluation of QoL. Results: According to the CGI-Severity scale, 20.5% of the patients were borderline mentally ill, and 24.4% were mildly ill. The highest number of patients (34.6%) were moderately ill, while 14.1% and 2.6% were markedly ill and severely ill, respectively. Among the moderately ill patients, more than half (63%) were patients with schizophrenia, 18.5% were patients with delusional disorder, and 18.5% were patients with schizoaffective disorder. Most of the patients (43.6%) presented moderate functioning deficiency, while 38.5% of the patients presented severe deficiency, according to the GAFS score. When assessed with the ABAS, we observed that almost half of the patients (44.9%) showed an average functioning across skill areas in the conceptual, social, and practical domains. A percent of 67.9% of the patients presented an average QoL, while 15.4% and 12.8% showed a very low and low QoL. QoL was not influenced by the patients' symptomatology, gender, and education level. Having children, family support, better social and conceptual skills, and a higher perceived level of recovery was correlated with an increased QoL, hierarchical multiple regression R2 = 0.379, F(9, 68) = 2.616, and p = 0.012. Conclusions: Psychiatric interventions in psychosis should focus not only on symptoms' control, but also on improving social and family support, as well as adaptive skills to increase the patients' QoL.

Combining compensatory cognitive training and medication self-management skills training, in inpatients with schizophrenia: A three-arm parallel, single-blind, randomized controlled trial

OBJECTIVE

Cognitive impairment has a critical impact on functional outcomes in patients with schizophrenia. Compensatory cognitive training (CCT) has shown promise as a cognitive rehabilitation tool but little is known about its effectiveness when combined with medication self-management skills training (MSST) in patients with schizophrenia. Thus, this study compared the effects of a combined CCT and MSST with CCT and treatment as usual (TAU) on cognitive function, symptoms, and medication adherence.

METHOD

Eighty-seven inpatients with schizophrenia were randomly assigned to the TAU, CCT, or CCT + MSST groups. Assessments of cognitive function using the Brief Assessment of Cognition in Schizophrenia, symptoms using the Positive and Negative Syndrome Scale, and medication adherence using the Medication Adherence Questionnaire, were administered to all participants at baseline and at post-intervention.

RESULTS

Compared with the TAU group, the CCT group had significant improvements in verbal fluency, total cognitive function and medication adherence, and the CCT + MSST group had significant improvements in verbal fluency, total cognitive function, positive symptoms, and medication adherence. Compared with the CCT group, the CCT + MSST group had significant improvements in total cognitive function.

CONCLUSIONS

These results indicate that the integrated intervention may be more advantageous than CCT alone in improving total cognitive function and positive symptoms. Future research should seek to further explore the long-term effects of such a joint intervention.

Thought Suppression in Primary Psychotic Disorders and Substance/Medication Induced Psychotic Disorder

Introduction: First episode-psychosis (FEP) represents a stressful/traumatic event for patients. To our knowledge, no study to date has investigated thought suppression involved in FEP in a Romanian population. Our objective was to investigate thought suppression occurring during FEP within primary psychotic disorders (PPD) and substance/medication induced psychotic disorders (SMIPD). Further, we examined the relationship between thought suppression and negative automatic thoughts within PPD and SMIPD. Methods: The study included 30 participants (17 females) with PPD and 25 participants (10 females) with SMIPD. Psychological scales were administered to assess psychotic symptoms and negative automatic thoughts, along a psychiatric clinical interview and a biochemical drug test. Results: Participants in the PPD group reported higher thought suppression compared to SMIPD group. For the PPD group, results showed a positive correlation between thought suppression and automatic thoughts. For the SMIPD group, results also showed a positive correlation between thought suppression and automatic thoughts. Conclusions: Patients with PPD rely more on thought suppression, as opposed to SMIPD patients. Thought suppression may be viewed as an unhealthy reaction to FEP, which is associated with the experience of negative automatic thoughts and might be especially problematic in patients with PPD. Cognitive behavioral therapy is recommended to decrease thought suppression and improve patients’ functioning.

Rasch analysis of the PANSS negative subscale and exploration of negative symptom trajectories in first-episode schizophrenia - data from the OPTiMiSE trial

The observed heterogeneity in negative symptom treatment response may be partly attributable to inadequate measurement tools or limitations in methods of analysis. Previous Item Response Theory models of the Positive and Negative Syndrome Scale (PANSS) have only examined samples of chronic patients and with mixed results. We examined the scalability of the negative subscale embedded in the PANSS and subsequently explored negative symptom trajectories across four weeks of amisulpride treatment. Data were derived from the OPTiMiSE trial comprising 446 patients with first-episode schizophrenia or schizophreniform disorder. Using the Rasch Model to examine psychometric properties of the PANSS negative subscale, we found that the composite score across items was not an adequate measure of negative symptom severity. Consequently, we chose an exploratory statistical approach involving Principal Component Analysis which yielded one significant component clustering into two significant symptom trajectories: 1) Subtle but constant decrease in negative symptom severity (N = 323; 72%), and 2) symptom instability across visits (N = 19; 4%). Explorative analytic methods as presented here may pave the way for more efficient and sensitive methods of analyzing negative symptom response in research and in clinical practice.

M. Staging of Schizophrenia With the Use of PANSS: An International Multi-Center Study

INTRODUCTION

A specific clinically relevant staging model for schizophrenia has not yet been developed. The aim of the current study was to evaluate the factor structure of the PANSS and develop such a staging method.

METHODS

Twenty-nine centers from 25 countries contributed 2358 patients aged 37.21 ± 11.87 years with schizophrenia. Analysis of covariance, Exploratory Factor Analysis, Discriminant Function Analysis, and inspection of resultant plots were performed.

RESULTS

Exploratory Factor Analysis returned 5 factors explaining 59% of the variance (positive, negative, excitement/hostility, depression/anxiety, and neurocognition). The staging model included 4 main stages with substages that were predominantly characterized by a single domain of symptoms (stage 1: positive; stages 2a and 2b: excitement/hostility; stage 3a and 3b: depression/anxiety; stage 4a and 4b: neurocognition). There were no differences between sexes. The Discriminant Function Analysis developed an algorithm that correctly classified >85% of patients.

DISCUSSION

This study elaborates a 5-factor solution and a clinical staging method for patients with schizophrenia. It is the largest study to address these issues among patients who are more likely to remain affiliated with mental health services for prolonged periods of time.

Validation of the Russian Version of the Positive and Negative Syndrome Scale (PANSS-Ru) and Normative Data

Objective: The Positive and Negative Syndrome Scale (PANSS) is widely used to assess psychopathology. The Russian version (PANSSRu) has not been validated, and normative data for the Russian-speaking population currently do not exist. The aims of this study were to 1) complete linguistic validation for the PANSSRu, 2) perform psychometric validation of the Russian translation, and 3) present norms for the Russian and Belarusian population. Design: Validation and norms of the PANSS-Ru occurred in three stages-Stage I: linguistic validation; Stage II: psychometric validation of the translated version for 40 inpatients with schizophrenia and other psychoses; and Stage III: norms for 533 census-matched inpatients, outpatients, and healthy control subjects. Results: The rating criteria (PANSS-Ru), interview guide (SCI-PANSSRu), informant questionnaire (IQ-PANSS-Ru), and scoring form (PANSS QuikScore-Ru) were linguistically and psychometrically validated. Convergent validity between the PANSS subscale scores and total score with the Clinical Global Impressions-Severity Scale (CGI-S) were moderate (r=0.41-0.60) to high (r=0.61-0.80). Cronbach's α (0.88) verified internal consistency, and intra-class correlation coefficient (ICC) comparisons had a range of 0.83. Percentile normative data collected from 533 subjects are presented. Conclusion: This is the largest population-based study providing linguistic and psychometric validation of the PANSS-Ru. Normative data can provide clinicians with a benchmark of psychopathology and inform the efficacy of treatment interventions.

Disparity between General Symptom Relief and Remission Criteria in the Positive and Negative Syndrome Scale (PANSS): A Post-treatment Bifactor Item Response Theory Model

Objective: Total scale scores derived by summing ratings from the 30-item PANSS are commonly used in clinical trial research to measure overall symptom severity, and percentage reductions in the total scores are sometimes used to document the efficacy of treatment. Acknowledging that some patients may have substantial changes in PANSS total scores but still be sufficiently symptomatic to warrant diagnosis, ratings on a subset of 8 items, referred to here as the "Remission set," are sometimes used to determine if patients' symptoms no longer satisfy diagnostic criteria. An unanswered question remains: is the goal of treatment better conceptualized as reduction in overall symptom severity, or reduction in symptoms below the threshold for diagnosis? We evaluated the psychometric properties of PANSS total scores, to assess whether having low symptom severity post-treatment is equivalent to attaining Remission. Design: We applied a bifactor item response theory (IRT) model to post-treatment PANSS ratings of 3,647 subjects diagnosed with schizophrenia assessed at the termination of 11 clinical trials. The bifactor model specified one general dimension to reflect overall symptom severity, and five domain-specific dimensions. We assessed how PANSS item discrimination and information parameters varied across the range of overall symptom severity (θ), with a special focus on low levels of symptoms (i.e., θ<-1), which we refer to as "Relief" from symptoms. A score of θ=-1 corresponds to an expected PANSS item score of 1.83, a rating between "Absent" and "Minimal" for a PANSS symptom. Results: The application of the bifactor IRT model revealed: (1) 88% of total score variation was attributable to variation in general symptom severity, and only 8% reflected secondary domain factors. This implies that a general factor may provide a good indicator of symptom severity, and that interpretation is not overly complicated by multidimensionality; (2) Post-treatment, 534 individuals (about 15% of the whole sample) scored in the "Relief" range of general symptom severity, but more than twice that number (n = 1351) satisfied Remission criteria (37%). 2 in 3 Remitted patients had scores that were not in a low symptom range (corresponding to Absent or Minimal item scores); (3) PANSS items vary greatly in their ability to measure the general symptom severity dimension; while many items are highly discriminating and relatively "pure" indicators of general symptom severity (delusions, conceptual disorganization), others are better indicators of specific dimensions (blunted affect, depression). The utility of a given PANSS item for assessing a patient depended on the illness level of the patient. Conclusion: Satisfying conventional Remission criteria was not strongly associated with low levels of symptoms. The items providing the most information for patients in the symptom Relief range were Delusions, Preoccupation, Suspiciousness Persecution, Unusual Thought Content, Conceptual Disorganization, Stereotyped Thinking, Active Social Avoidance, and Lack of Judgment and Insight. Lower scores on these items (item scores ≤2) were strongly associated with having a low latent trait θ or experiencing overall symptom relief. The inter-rater agreement between Remission and Relief subjects suggested that these criteria identified different subsets of patients. Alternative subsets of items may offer better indicators of general symptom severity and provide better discrimination (and lower standard errors) for scaling individuals and judging symptom relief, where the "best" subset of items ultimately depends on the illness range and treatment phase being evaluated.

A Developmental History of the Positive and Negative Syndrome Scale (PANSS)

Psychometric instruments are products of their time-Their designs and initial purposes are influenced and shaped by the contemporary treatment regimens, context, and cultural and conceptual biases of their developers. In this review article, the authors explore the history of the most influential schizophrenia research tools that have been created over the past several decades. The authors describe the scientific concepts, cultural influences, and challenges of past and present researchers as they strive to develop better assessment tools for schizophrenia. Starting with Moore's Scheme for the Quantitative Measurement of Abnormal Emotional Condition, developed in the early 1900s, and concluding with Kay, Fiszbein, and Opler's Positive and Negative Syndrome Scale, developed in the 80s, the authors describe several scales and illustrate how each scale led to and influenced the development of a later scale. The authors hope that a better understanding of schizophrenia assessment tool evolution and limitations will assist in the development of new instruments that better address the global needs for the evaluation, research, and treatment of psychosis.

Negative Symptom Dimensions of the Positive and Negative Syndrome Scale Across Geographical Regions: Implications for Social, Linguistic, and Cultural Consistency

Objective: Recognizing the discrete dimensions that underlie negative symptoms in schizophrenia and how these dimensions are understood across localities might result in better understanding and treatment of these symptoms. To this end, the objectives of this study were to 1) identify the Positive and Negative Syndrome Scale negative symptom dimensions of expressive deficits and experiential deficits and 2) analyze performance on these dimensions over 15 geographical regions to determine whether the items defining them manifest similar reliability across these regions. Design: Data were obtained for the baseline Positive and Negative Syndrome Scale visits of 6,889 subjects across 15 geographical regions. Using confirmatory factor analysis, we examined whether a two-factor negative symptom structure that is found in schizophrenia (experiential deficits and expressive deficits) would be replicated in our sample, and using differential item functioning, we tested the degree to which specific items from each negative symptom subfactor performed across geographical regions in comparison with the United States. Results: The two-factor negative symptom solution was replicated in this sample. Most geographical regions showed moderate-to-large differential item functioning for Positive and Negative Syndrome Scale expressive deficit items, especially N3 Poor Rapport, as compared with Positive and Negative Syndrome Scale experiential deficit items, showing that these items might be interpreted or scored differently in different regions. Across countries, except for India, the differential item functioning values did not favor raters in the United States. Conclusion: These results suggest that the Positive and Negative Syndrome Scale negative symptom factor can be better represented by a two-factor model than by a single-factor model. Additionally, the results show significant differences in responses to items representing the Positive and Negative Syndrome Scale expressive factors, but not the experiential factors, across regions. This could be due to a lack of equivalence between the original and translated versions, cultural differences with the interpretation of items, dissimilarities in rater training, or diversity in the understanding of scoring anchors. Knowing which items are challenging for raters across regions can help to guide Positive and Negative Syndrome Scale training and improve the results of international clinical trials aimed at negative symptoms.

Could PANSS be a useful tool in the determining of the stages of schizophrenia? A clinically operational approach

Staging in schizophrenia might be an important approach for the better treatment and rehabilitation of patients. The purpose of this study was to empirically devise a staging approach in a sample of stabilized patients with schizophrenia. One hundred and seventy patients aged ≥18 years (mean = 40.7, SD = 11.6) diagnosed by DSM-5 criteria were evaluated with the Positive and Negative Syndrome Scale (PANSS). Principal components analysis (PCA) with varimax rotation was used. The model was examined in the total sample and separately across a hypothesized stage of illness based on three age groups and between the two sexes. The PCA revealed a six factor structure for the total sample: 1) Negative, 2) Positive, 3) Depression and anxiety, 4) Excitement and Hostility, 5) Neurocognition and 6) Disorganization. The separate PCAs by stage of illness and sex revealed different patterns and quality of symptomatology. The Negative and Positive factors were stable across all examined groups. The models corresponding to different stages differed mainly in terms of neurocognition and disorganization and their interplay. Catatonic features appear more prominent in males while in females neurocognition takes two forms; one with disorganization and one with stereotype thinking with delusions. This study suggests that the three arbitrary defined stages of illness (on the basis of age) seem to reflect a progress from a preserved insight and more coherent mental functioning to disorganization and eventually neurocognitive impairment. Sexes differ in terms of the relationship of psychotic features with neurocognition. These results might have significant research and clinical implications.

PANSS-6: a brief rating scale for the measurement of severity in schizophrenia

OBJECTIVE

The 30-item Positive and Negative Syndrome Scale (PANSS-30) is the most widely used rating scale in schizophrenia, but too long for clinical use. Shorter PANSS versions have been proposed, including the PANSS-14 and PANSS-8. However, none of these PANSS versions has been validated using the parametric Rasch rating scale model, which evaluates 'scalability'. Scalability means that each item in a rating scale provides unique information regarding syndrome severity and is a statistical prerequisite for using the total score as a measure of overall severity.

METHOD

Based on data from two randomized placebo-controlled trials in schizophrenia, we tested the scalability of PANSS-30, PANSS-14 and PANSS-8 by means of the parametric Rasch rating scale model. Furthermore, we tested whether a scalable PANSS version could separate efficacy of haloperidol and sertindole from placebo.

RESULTS

Neither PANSS-30, PANSS-14 nor PANSS-8 was scalable. However, PANSS-6, consisting of the items: P1-Delusions, P2-Conceptual disorganization, P3-Hallucinations, N1-Blunted Affect, N4-Social withdrawal, N6-Lack of spontaneity and flow of conversation, was scalable. Furthermore, PANSS-6 captured superior symptom reduction and higher remission rates during treatment with haloperidol and sertindole vs. placebo.

CONCLUSION

PANSS-6 is a short schizophrenia severity rating scale that adequately separates antipsychotic efficacy from that of placebo.

Validation of a five-factor model of a Chinese Mandarin version of the Positive and Negative Syndrome Scale (CMV-PANSS) in a sample of 813 schizophrenia patients

OBJECTIVES

The Positive and Negative Syndrome Scale (PANSS) is one of the most widely used instruments for measuring the severity of schizophrenia. However, until now, there has not been a published, validated Chinese Mandarin version of the five-factor model PANSS with confirmatory factor analysis (CFA) for schizophrenic patients in Taiwan.

METHODS

A total of 813 subjects were recruited. Internal consistency was evaluated with Cronbach's alpha coefficient. For test re-test reliability, 57 patients were reassessed and intra-class correlation coefficients were calculated. For validity, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) using a Structured Equation Model were implemented to identify the factor model.

RESULTS

The Cronbach's alpha coefficient was 0.928. The intra-class coefficient was 0.878 (95% CI: 0.79-0.92). The final model was composed of five factors. EFA explained a total of 64.2% of the variance. CFA indicated a good fitting model. Except for the PANSS items G7 (motor retardation), G8 (uncooperativeness), N5 (abstract thinking), and G10 (disorientation), this study found that the items loaded on these factors were similar to the consensus items published in prior studies.

CONCLUSIONS

In summary, these findings support the Chinese Mandarin version of the PANSS as a reliable and valid instrument for the assessment of the severity of psychopathology in hospitalized, stable patients with schizophrenia. More effective and specific treatment models targeting sub-culture differences are expected to be developed in future studies.