Comorbid psychopathology and stress mediate the relationship between autistic traits and repetitive behaviours in adults with autism.
In adults with autism plus ID, untreated anxiety, mood issues, and stress drive repetitive behaviors, not executive-function deficits.
01Research in Context
What this study did
The team asked why repetitive behaviors stay strong in adults who have both autism and intellectual disability.
They measured autistic traits, stress, other mental-health problems, and executive-function slips.
Stats tests showed whether stress and comorbid psychopathology carry the effect from traits to repetitive behaviors.
What they found
Comorbid anxiety, mood, and other psychiatric symptoms plus stress explained most of the link.
Executive dysfunction added no extra power.
In short, treat the added mental-health pain first; the behaviors may then ease.
How this fits with other research
McCarthy et al. (2010) saw more challenging behavior in ASD+ID adults but could not pin it on comorbidity after controlling for age, gender, and ID level. Spriggs et al. (2015) used tighter mediation math and showed comorbidity and stress do carry the effect, updating the earlier picture.
Leung et al. (2014) found emotion dysregulation tied to repetitive behaviors in autistic youth. The adult data now extend that emotion–behavior link across the lifespan and flag treatable psychiatric diagnoses as the lever.
Three lab studies tie executive problems to repetitive behaviors: Hoyle et al. (2022) saw behaviors spike when kids face double EF loads, Johnson et al. (2009) linked EF scores to repetitive symptoms in high-functioning children, and Liu et al. (2025) showed EF mediates eating problems. Spriggs et al. (2015) found no EF effect, but their real-world survey differed in method, IQ range, and outcome, so the ideas clash only on the surface.
Why it matters
Before you shape a behavior plan for an adult with ASD+ID, run brief screens for anxiety, depression, and life stress. Adding coping skills, psychiatric care, or stress breaks may drop repetitive behaviors without touching the autism program.
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02At a glance
03Original abstract
BACKGROUND: Comorbid psychopathology and stress were considered possible mediators that may explain the relationship between some autistic traits and repetitive behaviours. The current study sought to examine the mediational effects of comorbid psychopathology, executive dysfunctions and stress in the relationship between some autistic traits and repetitive behaviours. METHOD: A battery of questionnaires including measures of autistic traits, repetitive behaviours, stress, executive dysfunctions and comorbid psychopathology were administered to a sample of adults with autism and intellectual disabilities (n = 43). RESULTS: We found that when taken as set dimensions of comorbidity, dysexecutive functioning and stress mediated or explained the effects of autistic symptoms on repetitive behaviour. The total model explained 60% of the variation in repetitive behaviours (R = 0.60; F = 13.64, P < 0.001). The results are discussed in the light of pertinent previous research and their clinical implications, and suggestions for future research are provided. CONCLUSIONS: According to the investigated model, increased levels of comorbid psychopathology and stress explained the relationships between repetitive/restrictive behaviours and autistic traits in adults with autism, while executive functioning did not contribute to that relationship.
Journal of intellectual disability research : JIDR, 2015 · doi:10.1111/jir.12083