Quantifying the core deficit in classical schizophrenia

Rathnaiah, Mohanbabu; Liddle, Elizabeth; Gascoyne, Lauren; Kumar, Jyothika; Zia Ul Haq Katshu, Mohammad; Faruqi, Catherine; Kelly, Christina; Gill, Malkeet; Robson, Sian; Brookes, Matt; Palaniyappan, Lena; Morris, Peter; Liddle, Peter F

Abstract

In the classical descriptions of schizophrenia, Kraepelin and Bleuler recognised disorganization and impoverishment of mental activity as fundamental symptoms. Their classical descriptions also included a tendency to persisting disability. The psychopathological processes underlying persisting disability in schizophrenia remain poorly understood. The delineation of a core deficit underlying persisting disability would be of value in predicting outcome and enhancing treatment. We tested the hypothesis that mental disorganization and impoverishment are associated with persisting impairments of cognition and role-function, and together reflect a latent core deficit that is discernible in cases diagnosed by modern criteria. We used Confirmatory Factor Analysis to determine whether measures of disorganisation, mental impoverishment, impaired cognition and role functioning in 40 patients with schizophrenia represent a single latent variable. Disorganization scores were computed from the variance shared between disorganization measures from three commonly used symptom scales. Mental impoverishment scores were computed similarly. A single factor model exhibited a good fit, supporting the hypothesis that these measures reflect a core deficit.Persisting brain disorders are associated with a reduction in Post Motor Beta Rebound (PMBR), the characteristic increase in electrophysiological beta amplitude that follows a motor response. Patients had significantly reduced PMBR compared with healthy controls. PMBR was negatively correlated with core deficit score.While the symptoms constituting impoverished and disorganised mental activity are dissociable in schizophrenia, nonetheless, the variance that these two symptom domains share with impaired cognition and role function, appears to reflect a pathophysiological process that might be described as the core deficit of classical schizophrenia.

Citation

Rathnaiah, M., Liddle, E., Gascoyne, L., Kumar, J., Zia Ul Haq Katshu, M., Faruqi, C., …Liddle, P. F. (2020). Quantifying the core deficit in classical schizophrenia. Schizophrenia Bulletin Open, 1(1), Article sgaa031. https://doi.org/10.1093/schizbullopen/sgaa031

• Journal Article Type: Article
• Acceptance Date: Jun 14, 2020
• Online Publication Date: Jun 25, 2020
• Publication Date: Jun 25, 2020
• Deposit Date: Jun 26, 2020
• Publicly Available Date: Jun 26, 2020
• Journal: Schizophrenia Bulletin Open
• Electronic ISSN: 2632-7899
• Publisher: Oxford University Press (OUP)
• Peer Reviewed: Not Peer Reviewed
• Volume: 1
• Issue: 1
• Article Number: sgaa031
• DOI: https://doi.org/10.1093/schizbullopen/sgaa031
• Keywords: schizophrenia, disorganization, negative symptoms, mental impoverishment, post movement beta rebound, core deficit
• Public URL: https://nottingham-repository.worktribe.com/output/4711151
• Publisher URL: https://academic.oup.com/schizbullopen/article/1/1/sgaa031/5862427