Do paranoid delusions exist on a continuum with subclinical paranoia? A multi-method taxometric study.
There is widespread interest in whether psychosis exists on a continuum with healthy functioning. Previous research has implied that paranoia, a common symptom of psychosis, exists on a continuum but this has not been investigated using samples including both patients and non-patients and up-to-date taxometric methods.



To assess the latent structure of paranoia in a diverse sample using taxometric methods.



We obtained data from 2836 participants, including the general population as well as at-risk mental state and psychotic patients using the P-scale of the Paranoia and Deservedness Scale. Data were analysed using three taxometric procedures, MAMBAC, MAXEIG and L-MODE (Ruscio, 2016), and two sets of paranoia indicators (subscales and selected items from the P scale), including and excluding the patient groups.



Eleven of the twelve analyses supported a dimensional model. Using the full sample and subscales as indicators, the MAMBAC analysis was ambiguous. Overall, the findings converged on a dimensional latent structure.



A dimensional latent structure of paranoia implies that the processes involved in sub-clinical paranoia may be similar to those in clinical paranoia.
University of Liverpool, Institute of Psychology, Health and Society, Waterhouse Building, Block B, Brownlow St, Liverpool L69 3GL, United Kingdom. Electronic address: hlaelahi@liverpool.ac.uk.
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Elahi
Lancaster University, Spectrum Centre for Mental Health Research, Furness Building C73, Lancaster LA1 4YG, United Kingdom. Electronic address: g.perezalgorta@lancaster.ac.uk.
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Perez Algorta
University of Manchester, Division of Psychology and Mental Health, School of Health Sciences, Zochonis Building, Manchester M13 9PL, United Kingdom. Electronic address: filippo.varese@manchester.ac.uk.
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Varese
University of Liverpool, Institute of Psychology, Health and Society, Waterhouse Building, Block B, Brownlow St, Liverpool L69 3GL, United Kingdom. Electronic address: j.mcintyre@liverpool.ac.uk.
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McIntyre
University of Liverpool, Institute of Psychology, Health and Society, Waterhouse Building, Block B, Brownlow St, Liverpool L69 3GL, United Kingdom. Electronic address: rpb@liverpool.ac.uk.
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Bentall
D000328:Adult; D003702:Delusions / Q000145:classification; D005260:Female; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D010258:Paranoid Behavior / Q000145:classification*; D010259:Paranoid Disorders / Q000145:classification*; D025341:Principal Component Analysis; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000145:classification / Q000523:psychology; D012306:Risk; D055815:Young Adult
Dimensional; L-MODE; MAMBAC; MAXEIG; Paranoia; Taxometrics