Effects of mindfulness- and acceptance-based interventions for individuals with schizophrenia spectrum disorders: A...

Mindfulness- and acceptance-based interventions (MBIs/ABIs) for persons with schizophrenia spectrum disorders (SSD) aim to cultivate purposeful attention, mind-body awareness, and targeted action-taking. This systematic meta-review assessed the current body of evidence regarding the effects of MBIs/ABIs for SSD symptoms.

The study was registered with PROSPERO (CRD42024535284) on June 3, 2024. Seven databases were searched between April 18 and April 19, 2024. Meta-analyses investigating the effects of MBIs/ABIs for SSD symptoms were considered. Two authors (AM, AS) independently completed data extraction and analysis. Evidence grading and methodology assessments were conducted using the Ioannidis' criteria, AMSTAR-2, and AMSTAR-Plus Content guidelines.

A total of 18 meta-analyses with up to 2572 participants were considered; 14 studies were eligible for analysis. Results were classified according to Ioannidis' criteria; the effect size of the highest ranked study with the largest number of primary studies is presented. Percentages indicate the number of studies reporting significant results. Significant evidence was found at end of treatment for overall symptomatology (MBIs: 100 %, n = 9, g = -0·7 (total range: -0·417 to -1·152), 95% CI: [-1·052, -0·347], I² = 95·36; ABIs: 25 %, n = 29, g = -1·065 (total range: -0·1 to -1·065) [-1·371, -0·759], I² = 85·1), positive (MBIs: 50 %, n = 6, g = -0·296 (total range: -0·155 to -0·416) [-0·528, -0·064], I² = 34·69; ABIs: 33·33 %, n = 3, g = -0·602 (total range: -0·602 to 0·147) [-1·014, -0·191], I² = 0), negative (MBIs: 100 %, n = 8, g = -0·94 (total range: -0·384 to -0.98) [-1·466, -0·413], I² = 86·42; ABIs: 25 %, n = 2, g = -0·631 (total range: -0·028 to -0.631) [-1·108, -1·154], I² = 0), affective symptoms (MBIs: 50 %, n = 9, g = -0·971 (total range: -0·275 to -0·971) [-1·413, -0·529], I² = 91·32; ABIs: 33·33 %, n = 3, g = -0·854 (total range: -0·472 to -0·854) [-1·255, -0·453, I² = 0), social functioning (MBIs: 100 %, n = 7, g = -1·368 (total range: -0·452 to -1·368) [-2·194, -0·542], I² = 94·3; ABIs: g total range: -0·878 to 0·625), mindfulness (MBIs: 66·66 %, n = 5, g = -0·805 (total range: -0·488 to -1·429) [-1·16, -0·45], I² = 0; ABIs: 66·66 %, n = 1, g = -0·959 (total range: -0·391 to -0·959) [-1·788, -0·129], I² = NA), and acceptance (MBIs: g total range: -0·381 to 0·381; ABIs: 50 %, n = 4, g = -0·393 (total range: -0·393 to 0·398) [-0·673, -0·113], I² = 0). Possible explanations for the differences in effect sizes for MBIs and ABIs are explored. Methodological assessments ranked 'low' or 'critically low' for all meta-analyses.

Although subject to several limitations, significant small to large effect sizes were evident for overall symptomatology, mindfulness, and social functioning. Small to large effect sizes were found for positive, negative, and affective symptoms. Future research should incorporate additional risk of bias assessments, increased sample sizes, and consider cultural contexts (as the largest effect sizes were reported by studies with a majority of samples from Mainland China and Hong Kong) regarding the therapeutic benefits of MBIs/ABIs.

There was no funding source for this study.