The paranoia as defence model of persecutory delusions: a systematic review and meta-analysis

BackgroundAn influential psychological model of persecutory delusions proposed they are caused by a bias towards holding others responsible for negative events, which serves to prevent underlying low self-esteem from reaching awareness. An early (1994) version of the model predicted self-esteem would therefore be preserved in people with these delusions, whereas a later (2001) version suggested it would be unstable, and that there would be a discrepancy between their explicit and implicit self-esteem, with the latter being lower. Our aim was to perform the first comprehensive meta-analytical test of the key predictions of this model, taking into account evidence quality.MethodsReports identified in previous systematic reviews were collated. Electronic databases (i.e., PsycINFO, MEDLINE, EMBASE and Web of Science) were searched from 2012 to September 2016. The review was pre-registered (PROSPERO registration number: CRD42016032782). Cross-sectional data from case-control, longitudinal or experimental studies that examined self-esteem or the externalising attributional bias in individuals diagnosed with schizophrenia-spectrum disorder were eligible for meta-analyses of group differences, but only if at least 50% of participants with psychosis also had current persecutory delusions. Uncontrolled and longitudinal studies were included in meta-analyses of correlations and self-esteem instability, respectively. Study and outcome quality were assessed using the Agency for Healthcare Research and Quality (AHRQ) assessment tool, and a modified version of Grading of Recommendations Assessment, Development and Evaluation (GRADE), respectively.Results We screened 3053 records, examined 104 full-text reports, and included 64 eligible studies. Consistent with the predictions of both versions of the model, paranoia severity in psychosis was positively correlated with the degree of externalising attributional bias (k=21, N=1128, r=0.18, 95% CI 0.08, 0.27; moderate quality). People with persecutory delusions also had a greater ...