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Cognitive bias modification for paranoia (CBM-pa): a randomised controlled feasibility study in patients with distressing paranoid beliefs

Yiend, Jenny, Lam, Charlene, Schmidt, Nora, Crane, Bryony, Heslin, Margaret, Kabir, Thomas, McGuire, Philip, Meek, Christopher, Mouchlianitis, Elias, Peters, Emmanuelle, and others. (2022) Cognitive bias modification for paranoia (CBM-pa): a randomised controlled feasibility study in patients with distressing paranoid beliefs. Psychological Medicine, . ISSN 0033-2917. (doi:10.1017/S0033291722001520) (KAR id:96360)


Background: Cognitive Bias Modification for paranoia (CBM-pa) is a novel, theory-driven psychological intervention targeting the biased interpretation of emotional ambiguity associated with paranoia. Study objectives were (i) test the intervention's feasibility, (ii) provide effect size estimates, (iii) assess dose-response and (iv) select primary outcomes for future trials.

Methods: In a double-blind randomised controlled trial, sixty-three outpatients with clinically significant paranoia were randomised to either CBM-pa or an active control (text reading) between April 2016 and September 2017. Patients received one 40 min session per week for 6 weeks. Assessments were given at baseline, after each interim session, post-treatment, and at 1- and 3-months post-treatment.

Results: A total of 122 patients were screened and 63 were randomised. The recruitment rate was 51.2%, with few dropouts (four out of 63) and follow-up rates were 90.5% (1-month) and 93.7% (3-months). Each session took 30-40 min to complete. There was no statistical evidence of harmful effects of the intervention. Preliminary data were consistent with efficacy of CBM-pa over text-reading control: patients randomised to the intervention, compared to control patients, reported reduced interpretation bias (d = -0.48 to -0.76), improved symptoms of paranoia (d = -0.19 to -0.38), and lower depressed and anxious mood (d = -0.03 to -0.29). The intervention effect was evident after the third session.

Conclusions: CBM-pa is feasible for patients with paranoia. A fully powered randomised control trial is warranted.

Item Type: Article
DOI/Identification number: 10.1017/S0033291722001520
Additional information: For the purpose of open access, the author(s) has applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising.
Uncontrolled keywords: Cognitive bias modification; RCT; interpretation bias; paranoia; psychosis
Subjects: R Medicine
Divisions: Divisions > Division of Natural Sciences > Kent and Medway Medical School
Funders: National Institute for Health Research (
South London and Maudsley NHS Foundation Trust (
Medical Research Council (
King's College London (
Depositing User: Rachael Heller
Date Deposited: 27 Sep 2022 13:12 UTC
Last Modified: 27 Feb 2024 11:58 UTC
Resource URI: (The current URI for this page, for reference purposes)

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