Associations between belief inflexibility and dimensions of delusions: A meta‐analytic review of two approaches to assessing belief flexibility.

Objectives: Belief inflexibility has been suggested to maintain delusions. Different measures of assessing belief inflexibility have been developed, and it remains unclear whether patients with delusions display belief inflexibility similarly across measures. As delusions consist of multiple dimensions, the aim of this meta‐analytic review was to examine how belief inflexibility is related to different aspects of delusions (conviction, distress, and preoccupation) and to compare these associations between interview‐based and task‐based measures of belief inflexibility. Methods: We conducted a systematic database search (PsycINFO, PsycARTICLES, PubMed, and MEDLINE) and identified relevant articles using the following search items: belief*, delusion*, or overvalued idea*; psychosis or schizo*; flexib*, inflexib*, change, revision, or update. Meta‐analyses were conducted for each dimension of delusions and were reported according to the PRISMA guidelines. Results: A total of 16 studies, with a total sample of 1,065, were included in the analysis. Belief inflexibility was associated with global severity of delusions (Hedges' <italic>g </italic>=<italic> </italic>0.452, <italic>p </italic><<italic> </italic>.001). Specifically, all dimensions of delusions were significantly associated with belief inflexibility (conviction: Hedges' <italic>g </italic>=<italic> </italic>0.678, <italic>p </italic><<italic> </italic>.001; preoccupation: Hedges' <italic>g </italic>=<italic> </italic>0.274, <italic>p </italic>=<italic> </italic>.002; distress: Hedges' <italic>g </italic>=<italic> </italic>0.200, <italic>p </italic>=<italic> </italic>.025). There was no significant heterogeneity across studies for each dimension. Preliminary subgroup analysis did not find any significant between‐measure differences in the relationship between belief inflexibility and overall severity of delusions. Conclusions: Belief inflexibility, across measures, was robustly associated with delusions, with a particularly strong association for delusional conviction. Our results carried implications for process‐based interventions for delusions. Practitioner points: <italic><bold>Positive clinical implications</bold></italic> Belief inflexibility is consistently associated with the maintenance of delusions. Assessing belief inflexibility in routine clinical practice will inform psychological interventions for patients with persistent delusions. Interview‐ and task‐based measures of belief inflexibility may be used complementarily to facilitate our understanding of this reasoning bias. Aetiological factors may be more closely associated with some aspects of delusions than the others. In line with a multidimensional view of delusions, interventions targeting different dimensions of delusions may have different therapeutic emphases.<italic><bold>Limitations</bold></italic> The current review focused on three core dimensions of delusions only (conviction, preoccupation, distress). Other ways of dissecting delusions are possible. Comparisons between the two measures of belief inflexibility may benefit from further research. [ABSTRACT FROM AUTHOR]