Language Discrepancy and Aggressive Behaviors in Individuals with Autism Spectrum Disorder

Background: Individuals with Autism Spectrum Disorder often display deficits in language, with receptive skills frequently more developed than expressive (Tager-Flusberg & Kjelgaard, 2001). Aggression is also prevalent, with 1 in 4 individuals exhibiting these behaviors (Hill et al., 2014). Previous studies identified a relationship between language and aggression (Estrem, 2010) but have not examined the impact of a discrepancy in receptive and expressive skills on aggression.

Objectives: The current study used language and aggression scores to see if data replicated previous studies. This study first assessed for discrepancy between receptive and expressive language ability, and then assessed the correlation between the amount of discrepancy, direction of discrepancy, and possible relation to physical aggression levels.

Methods: Data on individuals with ASD (n = 713) aged 1.9 to 22.7 years was used from the Simons Simplex Collection and the Boston Autism Consortium. Diagnosis was verified using The Autism Diagnostic Observation Schedule and Autism Diagnostic Interview-Revised (ADI-R). The Vineland Adaptive Behavior Scales were used to measure receptive and expressive language skills. Aggression was measured by ADI-R items 81, 82, and 83: “aggression towards caregivers/family” and “towards non-caregivers/non-family” and “self-injurious behavior” on a 0-3 scale (0=not present). The ADI-R was used to evaluate participant’s age of onset of aggressive symptoms and the current presence or absence of aggression. We calculated a mean value for behaviors by averaging the current aggression scores (CAS).

Results: Results suggest that a majority of our cohort (65%) exhibited language delay and (70%) aggressive behaviors. 84% of the sample had discrepancies between their receptive and expressive language skills, with 8.5% being a statistically significant discrepancy and 6.5 % having significantly higher receptive language (HRL). There was a significant relationship between CAS and HRL (p=.011), with larger discrepancy related to higher (more severe) aggression. There was also a significant relationship between HRL and aggression towards caregivers/family (p=.034) as well as aggression towards self (p=.036). Results were not significant for non-caregiver/non-family members (p=.259).

Conclusions: Preliminary results suggest a significant relationship between HRL and CAS within the family, as well as for self-injurious behavior, whereas there was not a significant relationship between HRL and CAS for non-family members. The current study highlights the importance of examining receptive and expressive skills as separate variables within the context of current aggressive behaviors. Future directions include analyzing the sample of children who displayed higher expressive than receptive language skills within the context of aggression (2% displayed statistically significant higher expressive language skills).