Abstract
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.
Originalsprog | Engelsk |
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Tidsskrift | Acta Psychiatrica Scandinavica |
Vol/bind | 146 |
Udgave nummer | 1 |
Sider (fra-til) | 21-35 |
Antal sider | 15 |
ISSN | 0001-690X |
DOI | |
Status | Udgivet - 2022 |
Bibliografisk note
Funding Information:The Optimize study was funded by the European Commission within the 7th Program (HEALTH‐F2‐2010‐242114). This work was also supported by the Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Mental Health Center Glostrup, Denmark. The funding sources were not involved in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.
Funding Information:
SL declares fees for consulting from LB Pharma, Otsuka, Lundbeck, Boehringer Ingelheim, LTS Lohmann, Janssen, Johnson & Johnson, TEVA, MSD, Sandoz, SanofiAventis, Angelini, Recordati, Sunovion and Geodon Richter. SG declares honoraria, advisory board or consulting fees from Gedeon‐Richter, Janssen Pharmaceuticals, Janssen‐Cilag Polska Sp., Otsuka, Pierre Fabre and Sunovion Pharmaceuticals. AM declares honoraria, advisory board or consulting fees from Janssen Pharmaceuticals, Lundbeck, Otsuka, Pfizer and Pierre Faber. CA has been a consultant to or has received honoraria or grants from Acadia, Angelini, Boehringer, Gedeon Richter, Janssen Cilag, Lundbeck, Minerva, Otsuka, Roche, Sage, Servier, Shire, Schering Plow, Sumitomo Dainippon Pharma, Sunovion and Takeda. CDC holds a Juan Rodés grant from Instituto de Salud Carlos III, Spanish Ministry of Science and Innovation (JR19/00024) and has received fees from AbbVie, Sanofi, and Exeltis. BHE has received lecture fees and/or is part of Advisory Boards of Bristol‐Myers Squibb, Eli Lilly and Company, Janssen‐Cilag, Otsuka Pharma Scandinavia AB, Takeda Pharmaceutical Company, Boehringer Ingelheim, and H. Lundbeck A/S. RSK declares personal fees for consultancy from Alkermes, Minerva Neuroscience, Gedeon Richter, and Otsuka; and personal (speaker) fees from Otsuka/Lundbeck. BYG is the leader of a Lundbeck Foundation Centre of Excellence for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), which is partly financed by an independent grant from the Lundbeck Foundation. All grants are administered by the Mental Health Services in the Capital Region of Denmark. All other authors report no financial relationships with commercial interests.
Publisher Copyright:
© 2022 The Authors. Acta Psychiatrica Scandinavica published by John Wiley & Sons Ltd.