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

Clinical characteristics associated with functioning trajectories following admission to a psychiatric institution: A prospective cohort study of individuals with psychosis

Psychotic disorders can be severely enabling, and functional recovery is often difficult to achieve. Admission to a psychiatric unit represents a key opportunity to implement strategies that will improve functional outcomes. In the current literature, there is a lack of consensus on which factors influence functional recovery. Therefore, the present longitudinal cohort study aimed to identify factors associated with functional trajectories following hospital admission for acute psychosis. A sample of 453 individuals with acute psychosis was extracted from the Signature Biobank database. Participants were followed for up to a year following admission. Various clinical indicators were documented over time. Functional trajectories were calculated based on the World Health Organization Disability Assessment Schedule 2.0. Three groups were identified: "improving", "stable", and "worsening" function. Individuals with a more severe symptomatic presentation at baseline were found to have better functional improve more over time. Over time, individuals in the "improving" and "stable" groups had significant improvements in their psychiatric symptoms. Finally, individuals following a "worsening" functional trajectory initially improved in terms of psychotic symptoms, but it did not persist over time. These results highlight the importance of studying function as a key component of recovery rather than solely focusing on relapse prevention.

Fibre density and fibre-bundle cross-section of the corticospinal tract are distinctly linked to psychosis-specific symptoms in antipsychotic-naïve patients with first-episode schizophrenia

Multiple lines of research support the dysconnectivity hypothesis of schizophrenia. However, findings on white matter (WM) alterations in patients with schizophrenia are widespread and non-specific. Confounding factors from magnetic resonance image (MRI) processing, clinical diversity, antipsychotic exposure, and substance use may underlie some of the variability. By application of refined methodology and careful sampling, we rectified common confounders investigating WM and symptom correlates in a sample of strictly antipsychotic-naïve first-episode patients with schizophrenia. Eighty-six patients and 112 matched controls underwent diffusion MRI. Using fixel-based analysis (FBA), we extracted fibre-specific measures such as fibre density and fibre-bundle cross-section. Group differences on fixel-wise measures were examined with multivariate general linear modelling. Psychopathology was assessed with the Positive and Negative Syndrome Scale. We separately tested multivariate correlations between fixel-wise measures and predefined psychosis-specific versus anxio-depressive symptoms. Results were corrected for multiple comparisons. Patients displayed reduced fibre density in the body of corpus callosum and in the middle cerebellar peduncle. Fibre density and fibre-bundle cross-section of the corticospinal tract were positively correlated with suspiciousness/persecution, and negatively correlated with delusions. Fibre-bundle cross-section of isthmus of corpus callosum and hallucinatory behaviour were negatively correlated. Fibre density and fibre-bundle cross-section of genu and splenium of corpus callosum were negative correlated with anxio-depressive symptoms. FBA revealed fibre-specific properties of WM abnormalities in patients and differentiated associations between WM and psychosis-specific versus anxio-depressive symptoms. Our findings encourage an itemised approach to investigate the relationship between WM microstructure and clinical symptoms in patients with schizophrenia.

Attenuated niacin response is associated with a subtype of first-episode drug-naïve psychosis characterized as serious negative symptoms

Although the phenomenon of attenuated niacin response (ANR) has been widely replicated in some patients with first-episode psychosis (FEP), its relevance to the negative symptoms (NS) of psychosis remains unclear. Total of 240 patients with drug-naïve FEP and 101 healthy controls (HCs) were recruited, and 209 were followed up for 1 year. Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS), and niacin-induced responses were measured using laser Doppler flowmetry. We calculated the log-transform EC50 [concentration of methyl nicotinate required to elicit a half-maximal blood flow (MBF) response] and MBF values. Core-NS was generated by factor analysis of the PANSS-NS subscale and cluster analysis to produce subtypes. Significant differences were found in the log10 (EC50) values between the FEP and HC groups (p < 0.001), supporting the ANR in patients with FEP. A higher NS severity was found in the ANR subgroup than that in other patients. Factor analysis determined that a two-dimensional model included core NS and rigidity of thinking. The log10 (EC50) value was significantly associated with only the core NS. Cluster analysis revealed three subtypes-36.7% (cluster-1, n = 88), 16.7% (cluster-2, n = 40), and 46.7% (cluster-3, n = 112). Cluster-2 characterized by extensive NS appeared to have a more remarkable ANR and less symptomatic improvement than those with other clusters during follow-up. No significant changes were found in the niacin response trajectories between the baseline and follow-up. Our findings indicate a significant correlation between ANR and core NS in patients with FEP. ANR may be a potential biomarker for certain subtypes with NS-dominated characteristics and poor symptomatic remission.

Single trajectory treatment response for predominant negative symptoms: Post-hoc analysis of a clinical trial with cariprazine and risperidone

Examining the heterogeneity of negative symptoms of schizophrenia contributes to the identification of available treatment targets. Generally, prior evidence classified three to four symptom treatment response trajectory groups over the course of positive symptoms, yet, no evidence exists regarding the heterogeneity of medium-term response to predominant negative symptoms. The current post-hoc analysis aims to identify the heterogeneity in negative symptom treatment response trajectories among patients with predominant negative symptoms who received either cariprazine or risperidone for 26 weeks. Treatment response was analyzed based on the: the Positive and Negative Syndrome Scale Factor Score for Negative Symptoms (PANSS-FSNS), and the Clinical Global Impression Severity (CGIS) and Improvement (CGII) scales. To identify subgroups of patients with a similar course of treatment response, group-based trajectory modelling was utilized. Results demonstrated that in comparison with competing models, a single trajectory best described the treatment response of patients with predominant negative symptoms. The results indicate that patients with predominant negative symptoms with over ten years of schizophrenia respond rapidly to adequate treatment and follow a course of steady improvement.

Rasch analysis of the beck depression inventory in a homeless and precariously housed sample

The approach to analysis of and interpretation of findings from the Beck Depression Inventory (BDI), a self-report questionnaire, depends on sample characteristics. To extend work using conventional BDI scoring, the BDI's suitability in assessing symptom severity in a homeless and precariously housed sample was examined using Rasch analysis. Participants (n=478) recruited from an impoverished neighbourhood in Vancouver, Canada, completed the BDI. Rasch analysis using the partial credit model was done, and the structural validity, unidimensionality, and reliability of the BDI were studied. A receiver operating characteristic curve determined a Rasch cut-off score consistent with clinical depression, and Rasch scores were correlated with raw scores. Good fit to the Rasch model was observed after rescoring all items and removing Item 19 (Weight Loss), and unidimensionality and reliability were satisfactory. Item 9 (Suicidal Wishes) represented the most severe symptom. Rasch-based scores detected clinical depression with moderate sensitivity and specificity, and were positively correlated with conventional scores. The BDI in a community-based sample of homeless and precariously housed adults satisfied Rasch model expectations in a 20-item format, and is suitable for assessing symptom severity. Future research on depression in similar samples may reveal more information on using specific symptoms to determine clinical significance.

Scalability of the Positive and Negative Syndrome Scale in first-episode schizophrenia assessed by Rasch models

OBJECTIVE

Historically, assessment of the psychometric properties of the Positive and Negative Syndrome Scale (PANSS) has had several foci: (1) calculation of reliability indexes, (2) extraction of subdimensions from the scale, and (3) assessment of the validity of the total score. In this study, we aimed to examine the scalability and to assess the clinical performance of the 30-item PANSS total score as well as the scalability of a shorter version (PANSS-6) of the scale.

METHODS

A composite data set of 1073 patients with first-episode schizophrenia or schizophrenia spectrum disorder was subjected to Rasch analysis of PANSS data from baseline and 4-6 weeks follow-up.

RESULTS

The central tests of fit of the Rasch model failed to satisfy the statistical requirements behind item homogeneity for the PANSS-30 as well as the PANSS-6 total score. For the PANSS-30, Differential Item Functioning was pronounced both for the 7-point Likert scale rating categories and when dichotomizing the rating categories. Subsequently, the Rasch structure analysis in the context of dichotomized items was used to isolate and estimate a systematic error because of item inhomogeneity, as well as a random error. The size of the combined sources of error for the PANSS-30 total score approximated 20% which is often regarded as clinical cut-off between response versus no-response.

CONCLUSION

The results demonstrate the operational consequences of a lack of statistical fit of the Rasch model and suggest that the calculated measure of uncertainty needs to be considered when using the PANSS-30 total score.

Differential Effects of Aripiprazole and Amisulpride on Negative and Cognitive Symptoms in Patients With First-Episode Psychoses

INTRODUCTION

Aripiprazole is hypothesized to have an effect on negative and cognitive symptoms in schizophrenia. Likewise, amisulpride is one of the only second-generation antipsychotics with which an effect on negative symptoms is reported. In the present study, we compare the effect of aripiprazole and amisulpride in initially antipsychotic-naïve patients with first-episode psychoses.

METHODS

Psychopathology and cognitive measures from two consecutive cohorts of antipsychotic-naïve first episode psychotic patients were obtained before and after 6 weeks of antipsychotic monotherapy with either aripiprazole or amisulpride. Matched healthy controls were included to account for retest effects on the cognitive measures. Analyses of variance (repeated-measures ANOVA) were performed to detect effect of time and possible cohort^*time interactions.

RESULTS

Longitudinal data was obtained from 47 and 48 patients treated for 6 weeks with amisulpride or aripiprazole, respectively. For the Wallwork negative symptom dimension, there was a cohort^*time interaction [F _{(1, 93)} = 4.29, p = 0.041] and a significant effect of time [F _{(1, 93)} = 6.03, p = 0.016], which was driven by an improvement in patients treated with aripiprazole [t ₍₄₇₎ = 4.1, p < 0.001] and not observed in patients treated with amisulpride (p > 0.5). For the eight cognitive measures, no cohort^*time interaction was found and neither was cognitive improvement in any of the cohorts when accounting for retest effect.

CONCLUSION

Patients treated with aripiprazole improved on negative symptoms, which was not the case for patients treated with amisulpride. This may point to a general effect of a partial D2 receptor agonist on negative symptoms in patients with first-episode psychoses. There was, however, no improvement in cognitive functions.