The application of AMSTAR2 in 32 overviews of systematic reviews of interventions for mental and behavioural disorders: A cross-sectional study.

'A measurement tool to assess systematic reviews, version 2' (AMSTAR2) is a 16-item tool to critically appraise systematic reviews (SRs) of healthcare interventions. This study aimed to assess the methods and outcomes of AMSTAR2 appraisals in overviews of SRs of interventions for mental and behavioural disorders. The cross-sectional study was conducted using 32 overviews of SRs selected from three electronic databases in January 2021. Data items included overview and SR characteristics and AMSTAR2 appraisal methods and outcomes. Data were extracted by two authors independently and narratively synthesised using descriptive statistics (means ± SD and relative frequencies). SR characteristics were compared based on AMSTAR2 appraisal outcomes using chi-square tests. The 32 overviews appraised SRs of predominantly non-pharmacological interventions for mental disorders. AMSTAR2 appraisals were reported as confidence ratings in 25/32 overviews or individual item scores in 24/32 overviews. Most SRs/overview were non-Cochrane (mean = 94%), included RCTs only (mean = 77%) and were published before AMSTAR2 release (mean = 79%). The confidence ratings derived in 25 overviews for 349 SRs were predominantly critically low (68%). Confidence ratings were similar for SRs with RCTs only versus RCTs+non-RCTs or SRs published before versus after AMSTAR2 release, while Cochrane SRs received more high+moderate than low+critically low confidence ratings (p < 0.01). Confidence ratings derived based on AMSTAR2 do not differentiate among SRs of healthcare interventions except for Cochrane SRs that fulfil the criteria for high confidence ratings. AMSTAR2 items should be consulted to avoid common weaknesses in future SRs.