Structure of positive psychotic symptoms in individuals at clinical high risk for psychosis
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Author/Creator ORCID
Date
2020-04-26
Type of Work
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Citation of Original Publication
Azis, M, Rouhakhtar, PR, Schiffman, JE, Ellman, LM, Strauss, GP, Mittal, VA. Structure of positive psychotic symptoms in individuals at clinical high risk for psychosis. Early Intervention in Psychiatry. 2021; 15: 505–512. https://doi.org/10.1111/eip.12969
Rights
This is the peer reviewed version of the following article: Azis, M, Rouhakhtar, PR, Schiffman, JE, Ellman, LM, Strauss, GP, Mittal, VA. Structure of positive psychotic symptoms in individuals at clinical high risk for psychosis. Early Intervention in Psychiatry. 2021; 15: 505–512. https://doi.org/10.1111/eip.12969, which has been published in final form at https://doi.org/10.1111/eip.12969. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.
Subjects
Abstract
Aim
Positive symptoms are a critical dimension of psychopathology in psychotic disorders and are used as a criterion for diagnosis across the psychosis continuum. Although initially considered as one dimension, there is evidence for multidimensionality within positive symptoms. The positive symptom structure has not been examined in individuals at clinical high risk (CHR) for psychosis. Knowledge of the dimensional structure of positive symptoms within CHR may contribute to our understanding of the aetiology and trajectory of this key facet of psychosis.
Method
Exploratory factor analysis (EFA) was conducted on the Prodromal Questionnaire-Brief for 183 individuals meeting CHR criteria. Internal consistency was examined to determine the hierarchical structure of the data and alternative models were compared.
Results
EFA revealed a three factor model, grouping in to: perceptual abnormalities, grandiose/unusual delusions and persecutory/thought delusions, with a general factor accounting for 56% of the variance. Confirmatory factor analysis showed that a hierarchical model was the best fit. One item referring to nihilistic thoughts did not load on any factor.
Conclusion
There is a clear three-dimensional model, distinguishing perceptual abnormalities, and two subgroups of delusions in CHR individuals. The factors are similar to those found in psychotic disorders. The identification and comparison of symptomatic models is useful given the prominent role positive symptoms play in diagnosis, and is crucial to our understanding of the clinical progression of psychosis. This work may provide a useful tool for future studies examining correlations with varying symptom factors and disease progression in CHR.