Externalizing and personalizing biases in persecutory delusions: The relationship with poor insight and theory-of-mind

Robyn Langdon*, Tonia Corner, Jen McLaren, Philip B. Ward, Max Coltheart

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    81 Citations (Scopus)


    The presence of externalizing bias (EB) for negative events together with personalizing bias (PB) (a bias to blame others rather than circumstances) may jointly constitute a vulnerability to develop persecutory delusions (PDs). Whereas EB purportedly serves to defend a vulnerable self-concept by avoiding negative self-attributions and might therefore exacerbate poor insight, PB may reflect cognitive deficits, including theory-of-mind impairment. We investigated these proposals in 34 schizophrenic patients with a history of PDs and 21 healthy controls. Patients with moderate- to severe-PDs and patients without a current PD showed excessive EB which was, surprisingly, absent in patients with mild persecutory delusions (mild-PDs). That EB might wax and wane with fluctuating delusional intensity was interpreted in accord with a new dynamic model of attribution self-representation cycles [Bentall et al., 2000. PDs: A review and theoretical integration. Clinical Psychology Review, 21, 1143-1192]. As predicted, EB exacerbated poor insight. However, counter to predictions, theory-of-mind impairment did not increase PB, which was marked in all participants, whether clinical or non-clinical; instead, theory-of-mind impairment was also correlated with poor insight. Our findings indicate multiple pathways to poor insight, one of which is a theory-of-mind difficulty, impairing the capacity to simulate other perspectives for the purpose of critically evaluating one's own beliefs and circumstances.

    Original languageEnglish
    Pages (from-to)699-713
    Number of pages15
    JournalBehaviour Research and Therapy
    Issue number5
    Publication statusPublished - May 2006


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