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

Background: The objective of this study was to examine the cross-cultural differences of the PANSS across six geo-cultural regions. The specific aims are (1) to examine measurement properties of the PANSS; and (2) to examine how each of the 30 items function across geo-cultural regions. Methods: Data was obtained for 1,169 raters from 6 different regions: Eastern Asia (n = 202), India (n = 185), Northern Europe (n = 126), Russia and Ukraine (n = 197), Southern Europe (n = 162), United States (n = 297). A principle components analysis assessed unidimensionality of the subscales. Rasch rating scale analysis examined cross-cultural differences among each item of the PANSS. Results: Lower item values reflects items in which raters often showed less variation in the scores; higher item values reflects items with more variation in the scores. Positive Subscale: Most regions found item P5 (Excitement) to be the most difficult item to score. Items varied in severity from −0.93 [item P6. Suspiciousness/persecution (USA) to 0.69 item P4. Excitement (Eastern Asia)]. Item P3 (Hallucinatory Behavior) was the easiest item to score for all geographical regions. Negative Subscale: The most difficult item to score for all regions is N7 (Stereotyped Thinking) with India showing the most difficulty Δ = 0.69, and Northern Europe and the United States showing the least difficulty Δ = 0.21, each. The second most difficult item for raters to score was N1 (Blunted Affect) for most countries including Southern Europe (Δ = 0.30), Eastern Asia (Δ = 0.28), Russia and Ukraine (Δ = 0.22) and India (Δ = 0.10). General Psychopathology: The most difficult item for raters to score for all regions is G4 (Tension) with difficulty levels ranging from Δ = 1.38 (India) to Δ = 0.72. Conclusions: There were significant differences in response to a number of items on the PANSS, possibly caused by a lack of equivalence between the original and translated versions, cultural differences among interpretation of items or scoring parameters. Knowing which items are problematic for various cultures can help guide PANSS training and make training specialized for specific geographical regions

Use of NON-PARAMETRIC Item Response Theory to develop a shortened version of the Positive and Negative Syndrome Scale (PANSS)

<p>Abstract</p> <p>Background</p> <p>Nonparametric item response theory (IRT) was used to examine (a) the performance of the 30 Positive and Negative Syndrome Scale (PANSS) items and their options ((levels of severity), (b) the effectiveness of various subscales to discriminate among differences in symptom severity, and (c) the development of an abbreviated PANSS (Mini-PANSS) based on IRT and a method to link scores to the original PANSS.</p> <p>Methods</p> <p>Baseline PANSS scores from 7,187 patients with Schizophrenia or Schizoaffective disorder who were enrolled between 1995 and 2005 in psychopharmacology trials were obtained. Option characteristic curves (OCCs) and Item Characteristic Curves (ICCs) were constructed to examine the probability of rating each of seven options within each of 30 PANSS items as a function of subscale severity, and summed-score linking was applied to items selected for the Mini-PANSS.</p> <p>Results</p> <p>The majority of items forming the Positive and Negative subscales (i.e. 19 items) performed very well and discriminate better along symptom severity compared to the General Psychopathology subscale. Six of the seven Positive Symptom items, six of the seven Negative Symptom items, and seven out of the 16 General Psychopathology items were retained for inclusion in the Mini-PANSS. Summed score linking and linear interpolation was able to produce a translation table for comparing total subscale scores of the Mini-PANSS to total subscale scores on the original PANSS. Results show scores on the subscales of the Mini-PANSS can be linked to scores on the original PANSS subscales, with very little bias.</p> <p>Conclusions</p> <p>The study demonstrated the utility of non-parametric IRT in examining the item properties of the PANSS and to allow selection of items for an abbreviated PANSS scale. The comparisons between the 30-item PANSS and the Mini-PANSS revealed that the shorter version is comparable to the 30-item PANSS, but when applying IRT, the Mini-PANSS is also a good indicator of illness severity.</p

Use of non-parametric item response theory to develop a shortened version of the Positive and Negative Syndrome Scale (PANSS) for patients with schizophrenia

Nonparametric item response theory (IRT) was used to examine (a) the performance of individual Positive and Negative Syndrome Scale (PANSS) items and their options, (b) the effectiveness of various subscales to discriminate among individual differences in symptom severity, and (c) the development of an abbreviated version of the PANSS (Mini-PANSS) linking scores on the original PANSS. Option characteristic curves (OCCs) and Item Characteristic Curves (ICCs) were estimated to examine the probability of rating each of seven options within each of 30 PANSS items as a function of subscale severity, and summed-score linking was applied to items selected for the Mini-PANSS. Data were baseline PANSS scores from 7187 patients with Schizophrenia or Schizoaffective disorder who were enrolled between 1995 and 2005 in clinical trials. Results show that the majority of items forming the Positive and Negative subscales perform very well and better discriminate along symptoms severity compared to the General Psychopathology subscale. Six of the seven Positive Symptom items, six of the seven Negative Symptom items, and seven out of the 16 General Psychopathology items were selected for inclusion in the Mini-PANSS. Summed score linking and linear interpolation was able to produce a translation table for comparing total subscale scores on the Mini-PANSS to total subscale scores on the original PANSS. Results show scores on the subscales of the Mini-PANSS can be linked to scores on the original PANSS subscales with very little bias

O5.7. VIRTUAL REALITY FUNCTIONAL CAPACITY ASSESSMENT IN PATIENTS WITH SCHIZOPHRENIA: CORRELATES OF PERFORMANCE OF SOLITARY AND SOCIALLY RELEVANT TASKS

Abstract Background Performance-based functional capacity measures as treatment outcomes have evolved into the use of virtual reality (VR) assessments. These strategies assess functional skills with objectives that include realistic performance of everyday tasks. One such task, the Virtual Reality Functional Capacity Assessment Task (VRFCAT), has a series of objectives focused on meal preparation, travel and transit, shopping, and financial skills. There are 12 different objectives in the task, of which 5 are performed while home alone and the other 7 are performed outside of the participant’s virtual residence. The 5 at home tasks are solitary and the other 7 tasks have actual or implied social interactions. In this study, we examined the differential correlates of these solitary vs. socially relevant tasks. In so doing, we examined whether patients with more severe reduced emotional experience had differential challenges with the solitary vs. socially relevant tasks. We also examined whether performance on these two tasks was differentially associated with real-world functioning in domains of work, everyday activities, and social outcomes. Methods 158 patients with schizophrenia performed the VRFCAT, were tested with the MATRICS consensus cognitive battery (MCCB), were rated with the PANSS, and received informant ratings of everyday functioning. Negative symptom domains of reduced emotional experience and reduced expression were derived from PANSS scores using previously determined criteria. Analyses examined the correlations between VRFCAT subdomains, the two domains of negative symptoms, MCCB performance and everyday functioning. Results Reduced emotional experience, but not reduced expression, was correlated with socially relevant VRFCAT tasks and with informant ratings of real-world social functioning. Further, performance on the VRFCAT socially relevant tasks, but not the VRFCAT solitary tasks, shared variance with informant ratings of work outcomes. Finally, MCCB performance was associated with both sets of VRFCAT demands, but the socially relevant tasks shared considerably more variance with MCCB scores than the solitary tasks. Discussion Patients with higher scores on reduced emotional experience were able to validly engage in socially relevant VR simulations, as evidenced by systematic correlations with outcome measures. However, these patients had poorer performance on these tasks than solitary functional tasks. The differential validity of solitary vs. socially relevant VR simulations was supported by differences in the correlates of these two VR subdomains, suggesting that short forms of an assessment could also be constructed with a special focus on the ability to perform simulated tasks away from home in the community

Using the Positive and Negative Syndrome Scale (PANSS) to Define Different Domains of Negative Symptoms: Prediction of Everyday Functioning by Impairments in Emotional Expression and Emotional Experience

Reduced emotional experience and expression are two domains of negative symptoms. The authors assessed these two domains of negative symptoms using previously developed Positive and Negative Syndrome Scale (PANSS) factors. Using an existing dataset, the authors predicted three different elements of everyday functioning (social, vocational, and everyday activities) with these two factors, as well as with performance on measures of functional capacity. A large (n=630) sample of people with schizophrenia was used as the data source of this study. Using regression analyses, the authors predicted the three different aspects of everyday functioning, first with just the two Positive and Negative Syndrome Scale factors and then with a global negative symptom factor. Finally, we added neurocognitive performance and functional capacity as predictors. The Positive and Negative Syndrome Scale reduced emotional experience factor accounted for 21 percent of the variance in everyday social functioning, while reduced emotional expression accounted for no variance. The total Positive and Negative Syndrome Scale negative symptom factor accounted for less variance (19%) than the reduced experience factor alone. The Positive and Negative Syndrome Scale expression factor accounted for, at most, one percent of the variance in any of the functional outcomes, with or without the addition of other predictors. Reduced emotional experience measured with the Positive and Negative Syndrome Scale, often referred to as "avolition and anhedonia," specifically predicted impairments in social outcomes. Further, reduced experience predicted social impairments better than emotional expression or the total Positive and Negative Syndrome Scale negative symptom factor. In this cross-sectional study, reduced emotional experience was specifically related with social outcomes, accounting for essentially no variance in work or everyday activities, and being the sole meaningful predictor of impairment in social outcomes

Schizophrenia: measurements of psychopathology

A key problem in schizophrenia research is how to assess the effects of treatment interventions given the spectrum of schizophrenia symptoms and patients' functioning. Measuring symptoms is complex, because these symptoms cover a wide variety of psychopathologic domains. The commonly recognized domains are the positive, negative, cognitive, excitement, and depression domains. This article critically reviews some of the available assessment tools of these domains together with other associated syndromes. The instruments discussed cover the broad range of psychopathology found in patients who have schizophrenia

Virtual reality assessment of functional capacity in people with Schizophrenia: Associations with reduced emotional experience and prediction of functional outcomes

Virtual Reality (VR) approaches have had considerable success in measurement of functional capacity. However, it is not clear if factors other than cognitive impairment influence performance on VR measures. Many people with schizophrenia have significant negative symptoms and they could reduce engagement in assessment. 158 patients with schizophrenia performed the VRFCAT, were tested with the MCCB, were rated with the PANSS, and were rated on everyday functioning. Scores for reduced emotional experience and reduced expression were derived. Reduced emotional experience, but not reduced expression, was correlated with socially relevant VRFCAT subtasks and real-world social functioning. Performance on the socially relevant subtasks, but not the solitary subtasks, shared variance with work outcomes. MCCB performance was associated with both subdomains, but socially relevant subtasks shared more variance. Patients with higher reduced emotional experience validly engaged in socially relevant VR simulations, as indexed by correlations with outcome measures. These patients had poorer performance on socially relevant tasks than on solitary tasks. The differential validity of solitary vs. socially relevant simulations was supported by differences in correlates, suggesting that assessments with a focus on performance of simulated socially relevant tasks could be developed

T111. PANSS NEGATIVE SYMPTOM DIMENSIONS ACROSS GEOGRAPHICAL REGIONS: IMPLICATIONS FOR SOCIAL, LINGUISTIC AND CULTURAL CONSISTENCY

Abstract Background Recognizing the discrete dimensions that underlie negative symptoms in schizophrenia and how these dimensions are conceptualized across geographical regions may result in better understanding and treatment. The expressive-experiential distinction has been shown to have vast importance in relation to functional outcomes in schizophrenia. Previous studies have shown that the PANSS may not be equivalently rated across counties and cultures, suggesting regional differences in both symptom expression and rater judgment of symptom severity. Items that perform in markedly different ways across demographic, regional, cultural, or clinical severity characteristics may not offer valid representations of the target construct. 1) Will the expressive and experiential dimensions of the PANSS vary over 15 geographical regions and will the item ratings defining each dimension manifest similar reliability across these regions? 2) In large multi-center, international trials where data are combined, which of the two dimensions are disposed to social, linguistic and cultural inconsistency? Methods Data was obtained for the baseline PANSS visits of 6,889 subjects. Using Confirmatory Factor Analysis (CFA), we examined whether the expressive-experiential distinction would be replicated in our sample. We investigated the validity of the expressive-experiential distinction using Differential Item Functioning (DIF; Mantel-Haenszel) across 15 geographical regions – South America-Mexico, Austria-Germany, Belgium-Netherlands, Brazil, Canada, Nordic regions (Denmark, Finland, Norway, Sweden), France, Great Britain, India, Italy, Poland, Eastern Europe (Romania, Slovakia, Ukraine, Croatia, Estonia, Czech Republic), Russia, South Africa, and Spain - as compared to the United States. Results Expressive Deficit: More DIF was observed for items in the Expressive deficit factor than for items relating to experiential deficits. The following regions showed at least moderate to large DIF for all items: Austria-Germany, Nordic, France, and Poland. Of all the items, N3 Poor Rapport showed the most moderate and large DIF (n = 13; 86.67%) across countries, with 7 countries reporting large DIF. Similarly, N6 Lack of Spontaneity and Flow of Conversation showed moderate and large DIF for 66.67% countries (n=10). Experiential Deficit: Item G16 Active Social Avoidance reported negligible DIF for 14 of the 15 countries investigated (93.33%). Large DIF was observed for N2 Emotional Withdrawal and N4 Passive Apathetic Social Withdrawal for Brazil and India. Seven regions demonstrated no DIF across all items of the PANSS experiential deficit factor (South America-Mexico, Belgium-Netherlands, Nordic, Great Britain, Eastern Europe, Russia, and Spain). Overall, there were many fewer observed items with large DIF for PANSS experiential domain. Discussion These results suggest that the PANSS Negative Symptoms Factor can be better represented by a two-factor model than by a single-factor model. Additionally, the results show significant differences in ratings on the PANSS expressive items, but not the experiential items, across regions. This could be due to a lack of equivalence between the original and translated versions, cultural differences in the interpretation of items, rater training, or understanding of scoring anchors. Knowing which items are challenging for raters across regions can help guide PANSS training to improve results of international clinical trials aimed at negative symptoms

S11. GENETIC INFLUENCES ON LACK OF INSIGHT: THE ROLE OF CATECHOL-O-METHYLTRANSFERASE (COMT) GENE POLYMORPHISMS

Abstract Background One of the key risk factors for relapse in schizophrenia is poor insight. Genetic influences on poor insight have not yet been studied despite growing evidence to the extent of genetic contributions in schizophrenia. There is evidence of genetic associations for psychopathology symptom domains (Arnedo et al., 2015) and these domains are strongly associated with insight. Dysfunction of the catechol-O-methyltransferase (COMT) gene is shown to confer susceptibility to schizophrenia because of its catalytic activity for dopamine degradation. COMT Val allele more rapidly inactivates released dopamine than the Met allele, and is shown to be associated with cognitive performance such as working memory and attention, and influences ToM functioning by modulating the dopamine pathways. Since the role of COMT in schizophrenia remains questionable, we determined whether any association exists between COMT genotypes and clinical symptomatology (Lack of Insight and Judgment) in a large cohort of schizophrenia subjects. Methods 145 subjects with DSM-IV-TR schizophrenia or schizoaffective disorder were genotyped via saliva sampling. Subjects were evaluated on clinical symptoms (PANSS). Genotyping of the COMT Val158Met polymorphism was evaluated compared to PANSS Marder factors, including PANSS items Lack of Insight and Judgment. Results Of 145 subjects, data from 138 subjects were usable. Distribution of COMT genotype: Met/Met: 28 (20.29%), Val/Met: 61 (44.20%), and Val/Val: 49 (35.51%). There was no significant difference between mean PANSS total score Met/Met: 76.053 (SD 13.011), Met/Val: 78.001 (SD 12.489), Val/Val: 79.596 (SD 11.286). Patients with the COMT Val/Val genotype had significantly higher total score on the PANSS Item Lack of Insight than those with the Val/Met or Met/Met genotypes (p = 0.041). Patients with the COMT Val/Val genotype also had significantly higher scores on the PANSS Disorganized Factor than those with the COMT Val/Met genotype (p = 0.043). As an exploratory analysis, COMT Val/Met showed significant association with Blunted Affect (p = 0.039), but no other items of the negative symptom factor. Discussion Our findings support hypotheses regarding associations between COMT polymorphisms and lack of insight and judgment in schizophrenia. It is important that the exact mechanisms of genetic contribution to insight are delineated to aid the development of effective treatments and to identify prevention strategies