Abstract
BACKGROUND: Anxiety is common in youth on the autism spectrum and cognitive behavioural therapy (CBT) has been adapted to address associated symptoms. The aim of the current systematic review and meta-analysis was to examine the efficacy of CBT for reducing anxiety in autistic youth. METHOD: Searches of PubMed and Scopus databases were undertaken from January 1990 until December 2020. Studies were included if they consisted of randomised controlled trials (RCTs) using CBT to reduce anxiety in autistic youth. Separate random effects meta-analyses assessed anxiety ratings according to informant (clinician; parent; child), both at end-of-trial and at follow-up. RESULTS: A total of 19 RCTs met our inclusion criteria (833 participants: CBT N = 487; controls N = 346). Random effects meta-analyses revealed a large effect size for clinician rated symptoms (g = 0.88, 95% CI 0.55, 1.12, k = 11), while those for both parent (g = 0.40, 95% CI 0.24, 0.56; k = 18) and child-reported anxiety (g = 0.25, 95% CI 0.06, 0.43; k = 13) were smaller, but significant. These benefits were not however maintained at follow-up. Moderator analyses showed that CBT was more efficacious for younger children (for clinician and parent ratings) and when delivered as individual therapy (for clinician ratings). Using the Cochrane Risk of Bias 2 tool, we found concerns about reporting bias across most trials. CONCLUSIONS: The efficacy of CBT for anxiety in autistic youth was supported in the immediate intervention period. However, substantial inconsistency emerged in the magnitude of benefit depending upon who was rating symptoms (clinician, parent or child). Follow-up analyses failed to reveal sustained benefits, though few studies have included this data. It will be important for future trials to address robustness of treatment gains overtime and to further explore inconsistency in efficacy by informant. We also recommend pre-registration of methods by trialists to address concerns with reporting bias.