A systematic review and meta-analysis of suicidality in autistic and possibly autistic people without co-occurring intellectual disability

Abstract Background Suicidality is highly prevalent in autistic people without co-occurring intellectual disabilities, and high autistic traits are found in adults who have attempted suicide. However, prevalence rates for both autistic and possibly autistic people have not been synthesised meta-analytically. Aims To (1) calculate pooled prevalence estimates of suicidality in autistic people and possibly autistic people without co-occurring intellectual disability; (2) evaluate the influence of participant and study level characteristics on heterogeneity; and (3) determine the quality of evidence. Methods Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were followed. PsycINFO, Embase, MEDLINE and Web of Science were systematically searched from 1992 to January 25, 2022. Empirical quantitative studies reporting prevalence of suicidal ideation, suicide plans, or suicide attempts and behaviours were considered for inclusion. Random effects models were used to estimate pooled prevalence of each suicidality outcome with 95% confidence intervals. Heterogeneity was explored using sensitivity and moderator analyses. Results Data from 48,186 autistic and possibly autistic participants in 36 primary studies were meta-analysed. Pooled prevalence of suicidal ideation was 34.2% (95% CI 27.9–40.5), suicide plans 21.9% (13.4–30.4), and suicidal attempts and behaviours 24.3% (18.9–29.6). High levels of heterogeneity (I 2 > 75) were observed in all three analyses. Estimates did not differ between autistic or possibly autistic samples. Geographical location (p = 0.005), transgender or gender non-conforming samples (p