Cognitive behavioural therapy for the treatment of schizophrenia spectrum disorders: an umbrella review of meta-analyses of randomised controlled trials

Background Cognitive behavioural therapy (CBT) forms the standard psychotherapy for schizophrenia spectrum disorders (SSD). We aimed to summarize and evaluate the evidence on the effectiveness of CBT for SSD. Methods In this umbrella review, we searched PubMed, Embase, Cochrane Database, and PsychInfo, for metaanalyses of randomised controlled trials (RCTs) of CBT in SSD published between database inception up to Aug 18, 2023. Inclusion criteria were RCTs investigating individually provided CBT in a population of patients with SSD, compared to either standard care, treatment as usually, or any other psychosocial therapies. No restrictions concerning follow-up or language were applied. We used the "assessment of multiple systematic reviews" (AMSTAR -2) appraisal checklist for the evaluation of methodological quality of meta -analysis. We extracted summary metrics from eligible studies in duplicate. The strength of evidence was classified by the sample size, pvalue, excess significance bias, prediction intervals, significance of largest study, and heterogeneity. The strength of evidence was ranked according to established criteria as: convincing, highly suggestive, suggestive, weak, or not significant. Primary outcomes were general psychopathology, positive and negative symptoms. This study is registered in PROSPERO, CRD42022334671. Findings We found 26 eligible meta -analyses, of which 16 meta -analyses provided sufficient data. Using the AMSTAR -2, we found limitations in details concerning the selection of study design, quality of the search and reporting of funding in included meta -analyses. A minority of 42.9% of the comparisons showed a significant result in favor of CBT; 57.1% were non -significant with no convincing or highly suggestive evidence. Suggestive evidence was found in favor of CBT for general psychopathology (6.2%, N = 34 RCTs, effect size (ES) = -0.33 (-0.47; -0.19), I-2 = 67.93), delusions (16.7%, N = 27, ES = 0.36 (0.22; 0.51), I-2 = 50.47), and hallucinations (33.3%, N = 28, ES = 0.32 (0.19; 0.46), I-2 = 45.14) at the end of treatment (EoT). Weak (N = 34 RCTs, ES = -0.13 (-0.24; -0.02), I-2 = 51.28), or non -significant evidence (N = 28 RCTs, ES = 0.12 (-0.03; 0.27) I-2 = 64.63) was found for negative symptoms at EoT. At longer follow-up, evidence became weak or nonsignificant. Interpretation Findings suggest that the effectiveness of CBT on general and positive symptoms in SSD at EoT was small to medium, while we found inconsistent evidence for a sustainable effect. CBT has no convincing impact on other relevant outcomes. Guidelines may use these results to specify their recommendations. Funding None. Copyright (c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).