Validation of the Brief Negative Symptom Scale in Korean patients with schizophrenia

Clinical Assessment Interview for Negative Symptoms (CAINS): A Systematic Review of Measurement Properties

BACKGROUND AND HYPOTHESIS

Negative symptoms are very important for the overall loss of functioning observed in patients with schizophrenia. There is a need for valid tools to assess these symptoms.

STUDY DESIGN

We used the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) systematic review guideline to evaluate the quality of the clinical assessment interview for negative symptoms (CAINS) as a clinician-rated outcome measurement (ClinROM).

STUDY RESULTS

The search strategy resulted in the retrieval of 13 articles, 11 of which were included in this evaluation. In terms of risk of bias, most articles reported on measures of internal consistency and construct validity, which were overall of good quality. Structural validity, reliability, measurement error, and cross-cultural validity were reported with less than optimum quality. There was a risk of bias in ClinROM development. According to the updated criteria of good measurement properties, structural validity, internal consistency, and reliability showed good results. In contrast, hypothesis testing was somewhat poorer. Results for cross-cultural validity were indeterminate. According to the updated GRADE approach from the COSMIN group the scale received a moderate grade.

CONCLUSIONS

The COSMIN standard allows a judgment of the CAINS as an instrument with the potential to be recommended for use, but which requires further research to assess its quality, in particular in the domains of content validity, internal consistency, and cross-cultural validity.

Two and five-factor models of negative symptoms in schizophrenia are differentially associated with trait affect, defeatist performance beliefs, and psychosocial functioning

Recent factor analytic evidence supports both two-factor (motivation and pleasure, MAP; diminished expression, EXP) and five-factor (anhedonia, asociality, avolition, blunted affect, alogia) conceptualizations of negative symptoms. However, it is unclear whether these two conceptualizations of the latent structure of negative symptoms have differential associations with external correlates. The current study evaluated external correlates of the two- and five-factor structures by examining associations with variables known to have critical relations with negative symptoms: trait affect, defeatist performance beliefs, neurocognition, and community-based psychosocial functioning. Participants included a total of 245 outpatients diagnosed with schizophrenia who were rated on the Brief Negative Symptom Scale and completed a battery of additional measures during periods of clinical stability. These additional measures included the Positive and Negative Affect Schedule, Defeatist Performance Beliefs scale, MATRICS Consensus Cognitive Battery, and Level of Function Scale. Pearson correlations indicated differential patterns of associations between the BNSS scores and the external correlates. Support for the two-factor model was indicated by a stronger association of MAP with positive affect and psychosocial functioning, compared to EXP with neurocognition. Significance tests examining a differential magnitude of associations showed that the two-dimension negative symptom structure masked unique correlational relationships among the five negative symptom domains with neurocognition and social/vocational community functioning and captured unique patterns of correlation with trait affect. Support for the five-factor model was shown by a stronger association between Blunted Affect with Attention/Vigilance, and stronger associations between Avolition, Anhedonia, and Asociality with psychosocial functioning. Results offer support for both the two-dimension and five-domain model of negative symptoms as well as a hierarchical two-dimensions-five-domains model of negative symptoms. Findings may have implications for diagnostic criteria and descriptions of the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5), as well as possible treatment targets of negative symptoms.

Development and Validation of the Negative Symptom Inventory-Psychosis Risk

BACKGROUND AND HYPOTHESES

Early identification and prevention of psychosis is limited by the availability of tools designed to assess negative symptoms in those at clinical high-risk for psychosis (CHR). To address this critical need, a multi-site study was established to develop and validate a clinical rating scale designed specifically for individuals at CHR: The Negative Symptom Inventory-Psychosis Risk (NSI-PR).

STUDY DESIGN

The measure was developed according to guidelines recommended by the NIMH Consensus Conference on Negative Symptoms using a transparent, iterative, and data-driven process. A 16-item version of the NSI-PR was designed to have an overly inclusive set of items and lengthier interview to support the ultimate intention of creating a new briefer measure. Psychometric properties of the 16-item NSI-PR were evaluated in a sample of 218 CHR participants.

STUDY RESULTS

Item-level analyses indicated that men had higher scores than women. Reliability analyses supported internal consistency, inter-rater agreement, and temporal stability. Associations with measures of negative symptoms and functioning supported convergent validity. Small correlations with positive, disorganized, and general symptoms supported discriminant validity. Structural analyses indicated a 5-factor structure (anhedonia, avolition, asociality, alogia, and blunted affect). Item response theory identified items for removal and indicated that the anchor range could be reduced. Factor loadings, item-level correlations, item-total correlations, and skew further supported removal of certain items.

CONCLUSIONS

These findings support the psychometric properties of the NSI-PR and guided the creation of a new 11-item NSI-PR that will be validated in the next phase of this multi-site scale development project.

The Brief negative Symptom Scale (BNSS): a systematic review of measurement properties

BACKGROUND

Negative symptoms of schizophrenia are linked with poor functioning and quality of life. Therefore, appropriate measurement tools to assess negative symptoms are needed. The NIMH-MATRICS Consensus defined five domains for negative symptoms, which The Brief Negative Symptom Scale (BNSS) covers.

METHODS

We used the COSMIN guidelines for systematic reviews to evaluate the quality of psychometric data of the BNSS scale as a Clinician-Rated Outcome Measure (ClinROM).

RESULTS

The search strategy resulted in the inclusion of 17 articles. When using the risk of bias checklist, there was a generally good quality in reporting of structural validity and hypothesis testing. Internal consistency, reliability and cross-cultural validity were of poorer quality. ClinROM development and content validity showed inadequate results. According to the updated criteria of good measurement properties, structural validity, internal consistency and interrater reliability showed good results, while hypothesis testing showed poorer results. Cross-cultural validity and test-retest reliability were indeterminate. The updated GRADE approach resulted in a moderate grade.

CONCLUSIONS

We can potentially recommend the use of the BNSS as a concise tool to rate negative symptoms. Due to weaknesses in certain domains further validations are warranted.

Cluster analysis of negative symptoms identifies distinct negative symptom subgroups

The heterogeneity of schizophrenia has been acknowledged for decades because of the diverse presentation of symptoms, illness course, and treatment response noted between individuals diagnosed with the disorder. Cluster analysis has been used as a statistical method to determine whether schizophrenia subgroups might be identified based on symptom heterogeneity. However, there is very limited research examining whether heterogeneity in negative symptoms might be useful in establishing schizophrenia subtypes, particularly research examining newer models of negative symptoms based on five latent constructs including anhedonia, asociality, avolition, blunted affect, and alogia. The Brief Negative Symptom Scale was used to assess the five negative symptoms domains in a sample of 220 outpatients diagnosed with schizophrenia or schizoaffective disorder. Cluster analysis supported a four-cluster solution, comprising clusters of subjects with low negative symptoms (LNS), severe negative symptoms (SNS), and two clusters with moderate negative symptoms, one with predominantly elevated blunted affect (BA) and one with elevated avolition (AV). The LNS, SNS, BA, and AV clusters significantly differed on external validators including clinical characteristics, neurocognition, and functional outcome. Findings suggest that schizophrenia heterogeneity can be parsed according to negative symptom subtypes that have distinct clinical and neuropsychological profiles. Implications for diagnosis and treatment are discussed.

Defining negative symptoms remission in schizophrenia using the Brief Negative Symptom Scale

INTRODUCTION

This study aimed to propose criteria for negative symptoms remission (NSR) in schizophrenia using the Brief Negative Symptom Scale (BNSS).

MATERIAL AND METHODS

274 participants were assessed on the Positive and Negative Syndrome Scale (PANSS), BNSS and Social and Occupational Functioning Assessment Scale (SOFAS). Two criteria for NSR on the BNSS were proposed - NSR based on the BNSS domains scores (NSR_{BNSS_DOMAINS}) and NSR based on 5 key items of the BNSS (NSR_{BNSS_5ITEMS})_. A SOFAS score of 61 and above was considered as functional remission (FR). Logistic regressions were run to examine the association between FR and NSR. Receiver operating characteristic (ROC) curve analysis was performed for the NSR criteria on FR. Kappa agreement statistic was used to evaluate the agreement between the two NSR criteria.

RESULTS

Eighty-nine (32.5%) participants fulfilled NSR_{BNSS_DOMAINS} criterion whereas 70 (25.6%) participants fulfilled NSR_{BNSS_5ITEMS} criterion. The two NSR criteria had substantial agreement (Kappa statistic=0.797) with each other. Sixty-one (25.3%) participants were in FR. FR was significantly associated with NSR, irrespective of the criterion used. To predict FR, the Area Under the Curve for NSR_{BNSS_DOMAINS} and NSR_{BNSS_5ITEMS} were 0.761 (CI: 0.696-0.826, p<0.001) and 0.723 (CI: 0.656-0.790, p<0.001), respectively. Hence, both NSR criteria demonstrated a fair ability to discriminate between functional remitters and non-remitters.

CONCLUSIONS

Depending on the setting and needs, clinicians and researchers might employ either the full BNSS or an abbreviated 5-item BNSS scale to identify NSR in schizophrenia. More research is needed to further examine the validity of these criteria in schizophrenia.

Association of Negative Symptoms of Schizophrenia Assessed by the BNSS and SNS Scales With Neuropsychological Performance: A Gender Effect

Objective: The relationship between negative symptoms and neurocognitive performance in schizophrenia is well documented, but the mechanism of these connections remains unclear. The study aims to measure the relationship between the results on the new scales for the assessment of negative symptoms such as Brief Negative Symptom Scale (BNSS) and Self-evaluation of Negative Symptoms (SNS), and the results of some neurocognition tests. The second aim is to assess a possible gender effect on these associations. Methods: The study included 80 patients (40 men, 40 women) with schizophrenia, aged 19-63 (mean 38 years), during the improvement period (total PANSS score <80, unchanged pharmacological treatment in the last 3 weeks). They were assessed using the BNSS, SNS, Personal and Social Performance (PSP) scales, and the tests for neuropsychological performance such as the Trail Making Test (TMT-A, TMT-B), Stroop Color-Word Interference Test, Verbal fluency tests (VFT), Category fluency test (CFT), and Digit Symbol Substitution Test (DSST). Results: Male patients obtained higher scores than females on some PANSS and BNSS items. No gender differences were observed for the SNS scale. Female patients scored better in the PSP and CFT. In male patients, a significant positive correlation between the intensity of negative symptoms measured by the BNSS and the results of PSP with the Trail Making Test was observed. In female patients, we found a positive correlation between the results of BNSS and PSP with the Stroop Color-Word Interference Test. Conclusion: The obtained results confirm the relationship between negative symptoms and neurocognition in schizophrenia patients. However, in male and female patients such association was observed for different cognitive domains. Further research is needed to explain the nature of these differences.

Defining negative symptoms remission in schizophrenia using the Brief Negative Symptom Scale

INTRODUCTION

This study aimed to propose criteria for negative symptoms remission (NSR) in schizophrenia using the Brief Negative Symptom Scale (BNSS).

MATERIAL AND METHODS

274 participants were assessed on the Positive and Negative Syndrome Scale (PANSS), BNSS and Social and Occupational Functioning Assessment Scale (SOFAS). Two criteria for NSR on the BNSS were proposed - NSR based on the BNSS domains scores (NSRBNSS_DOMAINS) and NSR based on 5 key items of the BNSS (NSRBNSS_5ITEMS). A SOFAS score of 61 and above was considered as functional remission (FR). Logistic regressions were run to examine the association between FR and NSR. Receiver operating characteristic (ROC) curve analysis was performed for the NSR criteria on FR. Kappa agreement statistic was used to evaluate the agreement between the two NSR criteria.

RESULTS

Eighty-nine (32.5%) participants fulfilled NSRBNSS_DOMAINS criterion whereas 70 (25.6%) participants fulfilled NSRBNSS_5ITEMS criterion. The two NSR criteria had substantial agreement (Kappa statistic=0.797) with each other. Sixty-one (25.3%) participants were in FR. FR was significantly associated with NSR, irrespective of the criterion used. To predict FR, the Area Under the Curve for NSRBNSS_DOMAINS and NSRBNSS_5ITEMS were 0.761 (CI: 0.696-0.826, p<0.001) and 0.723 (CI: 0.656-0.790, p<0.001), respectively. Hence, both NSR criteria demonstrated a fair ability to discriminate between functional remitters and non-remitters.

CONCLUSIONS

Depending on the setting and needs, clinicians and researchers might employ either the full BNSS or an abbreviated 5-item BNSS scale to identify NSR in schizophrenia. More research is needed to further examine the validity of these criteria in schizophrenia.

Structure of Negative Symptoms in Schizophrenia: An Unresolved Issue

Background: Negative symptoms are core features of schizophrenia and very challenging to be treated. Identification of their structure is crucial to provide a better treatment. Increasing evidence supports the superiority of a five-factor model (alogia, blunted affect, anhedonia, avolition, and asociality as defined by the NMIH-MATRICS Consensus); however, previous data primarily used the Brief Negative Symptoms Scale (BNSS). This study, including a calibration and a cross-validation sample (n = 268 and 257, respectively) of participants with schizophrenia, used the Clinical Assessment Interview for Negative Symptoms (CAINS) to explore the latent structure of negative symptoms and to test theoretical and data-driven (from this study) models of negative symptoms. Methods: Exploratory factor analysis (EFA) was carried out to investigate the structure of negative symptoms based on the CAINS. Confirmatory factor analysis (CFA) tested in a cross-validation sample four competing theoretical (one-factor, two-factor, five-factor, and hierarchical factor) models and two EFA-derived models. Result: None of the theoretical models was confirmed with the CFA. A CAINS-rated model from EFA consisting of five factors (expression, motivation for recreational activities, social activities, vocational, and close/intimate relationships) was an excellent fit to the data (comparative fix index = 0.97, Tucker-Lewis index = 0.96, and root mean square error of approximation = 0.07). Conclusions: This study cannot support recent data on the superiority of the five-factor model defined by the NMIH-MATRICS consensus and suggests that an alternative model might be a better fit. More research to confirm the structure of negative symptoms in schizophrenia, and careful methodological consideration, should be warranted before a definitive model can put forward and shape diagnosis and treatment of schizophrenia.

What is the Best Latent Structure of Negative Symptoms in Schizophrenia? A Systematic Review

Background

Determining the best latent structure of negative symptoms in schizophrenia could benefit assessment tools, neurobiological research, and targeted interventions. However, no review systematically evaluated studies that assessed and validated latent models of negative symptoms.

Objective

To identify and evaluate existing latent structure models in the literature of negative symptoms and to determine the best model.

Method

Systematic search of MEDLINE, EMBASE, and Scopus on July 19, 2020, for confirmatory factor analysis models of negative symptoms in patients with schizophrenia. The available evidence was assessed through 2 sets of criteria: (1) study design quality—based on negative symptoms assessment and modeling strategy and (2) psychometric quality and model fit—based on fit indices and factor definition quality.

Results

In total, 22 studies (n = 17 086) from 9 countries were included. Studies differed greatly regarding symptom scales, setting, and sample size (range = 86–6889). Dimensional models included 2–6 factors (median = 4). Twelve studies evaluated competing models and adopted appropriate instruments to assess the latent structure of negative symptoms. The 5-factor and hierarchical models outperformed unitary, 2-factor, and 3-factor models on all direct comparisons, and most of the analyses derived from the Brief Negative Symptom Scale. Considering the quality criteria proposed, 5-factor and hierarchical models achieved excellent fit in just one study.

Conclusions

Our review points out that the 5-factor and hierarchical models represent the best latent structure of negative symptoms, but the immaturity of the relevant current literature may affect the robustness of this conclusion. Future studies should address current limitations regarding psychometric properties and also address biological and clinical validity to refine available models.

Validation of the Dutch Version of the Brief Negative Symptom Scale

PURPOSE

The Brief Negative Symptom Scale (BNSS) was developed to measure negative symptoms of schizophrenia. However, the Dutch translation of this instrument, called the "Korte Schaal voor Negatieve Symptomen" (KSNS), has not yet been validated. This study investigates the validity and reliability of this Dutch version of the instrument.

PATIENTS AND METHODS

The Psychotic Symptom Rating Scale (PSYRATS), Calgary Depression Scale for Schizophrenia (CDSS), the Health of the Nation Scale (HoNOS) and the KSNS were used for routine outcome monitoring to measure symptoms in 28 patients with a psychotic disorder who were being treated on a long-stay ward.

RESULTS

The internal consistency of the KSNS is fair to good. The inter-rater reliability is excellent. The concurrent validity is moderate but acceptable. The correlations between the KSNS and scales for depression and positive symptoms were not significant, which indicate good divergent validity.

CONCLUSION

Despite the small sample size of the current study, we conclude that the BNSS, called the KSNS in Dutch, appears to be a reliable and valid tool for investigating negative symptoms in detail in patients with psychotic disorders.