Anxiety and intellectual functioning in autistic children: A systematic review and meta-analysis.

Anxiety measures were often not validated for autistic children or children with intellectual disability, so different studies may not have measured the same thing. Most studies relied on parent report, which depends on the child communicating worries or the parent recognising anxiety behaviours, and these may be missed in children with intellectual disability. The correlation estimate was small and very variable across studies; removing one study lowered the estimate and reduced heterogeneity. The group comparison of children with and without intellectual disability was based on only four papers, and the main model was not significant; a significant difference appeared only after removing one study. Some studies did not report clearly whether children with intellectual disability were included, and the pattern differed across these groups. Three papers could not be included because authors did not provide data, and all three reported non-significant correlations, so the true effect may be slightly smaller.

Funding: Dr Joanne Tarver's contribution was made possible through funding from Autistica.

Do not conclude that autistic children with intellectual disability are less anxious. The lower anxiety scores in some analyses may reflect underdiagnosis and poor measurement, and the overall IQ-anxiety link was small and inconsistent.