Is language ability associated with behaviors of concern in autism? A systematic review.

This review systematically synthesized evidence on the association between structural language ability and behaviors of concern (BoC) in autism. Four databases were searched for studies that included >10 autistic participants, measures of structural language (content and/or form of language) and BoC, and an analysis of their association. BoCs included self-injurious behavior (SIB), aggression, tantrums, and externalizing behavior. Methodological quality of studies were assessed using the Newcastle Ottawa Scale. Forty-five publications (n = 11,961) were included. Forty studies were cross-sectional and five were prospective cohort studies. Over 70% of the studies investigating expressive language and SIB (n = 10), aggression (n = 5), tantrums (n = 3), and externalizing behavior (n = 17) reported an inverse association, where lower expressive language ability was associated with increased BoC. Eleven out of sixteen studies of combined expressive and receptive language reported an inverse relationship with SIB or aggression. All outcomes were rated as moderate to very low certainty of evidence. This review highlights evidence showing an inverse association between expressive or combined language ability and SIB, and externalizing behavior in autism. However, further high-quality studies that use standardized, consistent measures of language and behavior and investigate longitudinal associations are needed. Early detection and support for reduced structural language difficulties have substantial potential to assist in reducing BoC.