Rationale and protocol for a systematic review and meta-analysis on reduced data gathering in people with delusions

Abstract

BackgroundThe tendency to form conclusions based on limited evidence is known as the ‘jumping to conclusions’ (JTC) bias, and has been a much studied phenomena in individuals with psychosis. Previous reviews have supported the hypothesis that a JTC bias is particularly linked to the formation and maintenance of delusions. A new systematic review is required as a number of studies have since been published, and older reviews are limited by not systematically assessing methodological quality or the role of study design in influencing effect size estimates. This review aimed to investigate if there is an association between psychosis or delusions and JTC bias.MethodsThe current protocol outlines the background and methodology for this systematic review and meta-analysis. Eligible articles will be identified through searches of the electronic databases PsycInfo, PubMed and Medline using relevant search terms, supplemented by hand-searches of references within eligible articles and key review articles within the field. Eligibility criteria were as follows: studies must recruit individuals with: i) schizophrenia spectrum conditions or ii) experiences of delusions. Case-control, cross-sectional, observational and prospective designs will be included but treatment trials and experimental studies excluded. Studies must use the beads task to assess JTC or a conceptually equivalent task. The outcomes will be the average number of ‘draws to a decision’ in the beads task (or related variant) and the proportion of the sample judged to demonstrate a JTC bias. Literature searches, study selection, data extraction, risk of bias assessment and outcome quality assessment will be undertaken by two independent reviewers. Meta-analyses will be undertaken for continuous (mean number of ‘draws to a decision’) and binary outcomes (number of people classified as having JTC bias).DiscussionUnderstanding of the size of the JTC effect and the contexts within which it occurs is important both in terms of informing models of delusional thinking and in guiding treatments for those with delusions or psychosis. However, a definitive, up-to-date review and meta-analysis of the JTC bias is currently lacking. The proposed review will fill this gap and resolve key issues regarding the factors which moderate the JTC bias.PROSPERO registrationCRD42014007603 http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42014007603

Jumping to Conclusions About the Beads Task? A Meta-analysis of Delusional Ideation and Data-Gathering

“…Such a possibility is consistent with one of the larger beads task studies included in our meta-analysis, which found no evidence for an association between paranoia (in the context of paranoid delusions) and jumping to conclusions once the association between paranoia and general cognitive performance had been controlled for. 47 We anticipate that the upcoming meta-analysis by Taylor et al 34 will help clarify because they aim to quantify differences in data gathering between groups with delusions and control groups while exploring a variety of potential moderating variables.…”

“…79 Third, the beads task is rarely incentivised and motivation might explain some differences in performance. 80,81 We suggest that further progress in determining whether people with delusions jump to conclusions could be made by using meta-analysis to investigate between-group differences in beads task performance, 34 exploring new data-gathering paradigms that might overcome methodological limitations of the beads task, [80][81][82][83][84][85][86] examining more closely what evidence is available to participants at the point when they decide to stop drawing beads, 87 controlling for important aspects of individual variation, 47 and revisiting the original-and methodologically sophisticatedbeads task paradigm. 1…”

“…Taylor et al 34 recently preregistered a rationale and protocol for a meta-analysis that will examine whether the JTC bias is associated with clinical delusions. This protocol is methodologically sophisticated and promises to address limitations of the earlier systematic reviews and meta-analysis.…”

‘Jumping to conclusions’ data-gathering bias in psychosis and other psychiatric disorders — Two meta-analyses of comparisons between patients and healthy individuals

“…In addition, only 22 clinical and nonclinical samples, mostly with small sample sizes, were included. More importantly, they included studies regardless of their methodological quality and combined non-independent effects (using 47 effect sizes from 22 samples) (Ross, McKay, Coltheart, & Langdon, 2015;Taylor, Hutton, & Dudley, 2014).…”

“…Additional studies were manually searched from the reference lists of the identified papers, as well as relevant review and meta-analytic papers (Fine et al, 2007;Garety & Freeman, 2013;Ross et al, 2015;Taylor et al, 2014). To further identify any studies that potentially slipped through the above search procedure, we emailed authors of the articles included in the primary search for any recently published studies.…”