Examining the relationship between cognitive inflexibility and internalizing and externalizing symptoms in autistic children and adolescents: A systematic review and meta-analysis.

Compared to neurotypical peers, autistic adolescents show greater cognitive inflexibility (CI) which manifests at the behavioral and cognitive level and potentially increases vulnerability for the development of internalizing (INT) and externalizing (EXT) symptoms. This systematic review and meta-analysis explored the association between CI and INT/EXT in autistic adolescents. PubMed, EMBASE, MEDLINE, PsycINFO and Web of Science databases were searched to identify relevant studies until April 2022 (PROSPERO protocol: CRD42021277294). Systematic review included 21 studies (n = 1608) of CI and INT, and 15 studies (n = 1115) of CI and EXT. A pooled effect size using Pearson's correlation between CI and INT/EXT was calculated and the moderating effects of age, sex, IQ and study quality were investigated using meta-regressions. Sensitivity analyses were completed to investigate the impact of measure variance for CI and co-occurring ADHD on the overall effects. Greater CI is associated with increased INT (nine studies; n = 833; r = 0.39 (moderate effect), 95% confidence interval [0.32, 0.46]) and EXT (six studies; n = 295; r = 0.48 (large effect), 95% confidence interval [0.38, 0.58]). Results withheld when only using parental reports of CI and excluding autistic adolescents with co-occurring ADHD. Increased CI may be a transdiagnostic vulnerability factor that can increase autistic adolescents' rigid or perseverative patterns of unhelpful cognition and behaviors and reduce their ability to access psychological interventions. Addressing CI may improve autistic children and adolescents' engagement with psychological therapy for co-occurring mental health difficulties.