The 10-year trajectory of aggressive behaviours in autistic individuals.

This study followed autistic people for 10 years to understand aggressive behaviors. While over 60% showed aggressive behaviors initially, only 30% continued to have these behaviors throughout the study period. Children who were more hyperactive and impulsive were more likely to continue showing aggressive behaviors as they got older. The good news is that aggressive behaviors generally decreased with age for most participants.

This longitudinal study followed 229 autistic individuals over 10 years to examine aggressive behaviors. At baseline, 61.6% exhibited aggressive behaviors, but only 30% showed persistent aggression across the decade. The study found that higher levels of overactivity and impulsivity at baseline significantly predicted continued aggressive behaviors at both 3-year and 10-year follow-ups, with medium effect sizes. Sample sizes decreased substantially over time (229 to 54 participants).

Results suggest that while aggressive behaviors are common in autism, they tend to reduce with age. ADHD-related symptoms may serve as important clinical indicators for identifying individuals at risk for persistent aggression.

ADHD-related symptoms (overactivity, impulsivity) may serve as useful clinical markers for identifying autistic individuals at risk for persistent aggressive behaviors. Early identification could enable targeted interventions. The finding that aggressive behaviors typically decrease with age provides reassurance for families and informs realistic treatment expectations.

Substantial sample attrition (229 to 54 participants over 10 years) limits generalizability. Study relied on caregiver reports rather than direct observation. No information provided about interventions received during the study period that might have influenced outcomes.

Aggressive behaviours are common in people with neurodevelopmental conditions, contributing to poorer quality of life and placement breakdown. However, there is limited empirical research documenting the prevalence and persistence of aggressive behaviours in autism. In this longitudinal study, aggressive behaviours were investigated in a sample of autistic individuals over 10 years. Caregivers of autistic individuals, both with and without intellectual disability, completed questionnaires relating to the presence of aggressive behaviours at T1 [N = 229, mean age in years 11.8, standard deviation (SD) 5.9], T2 (T1 + 3 years, N = 81, mean age in years 15.1, SD 5.9) and T3 (T1 + 10 years, N = 54, mean age in years 24.5, SD 8.1).

Analyses examined the presence and persistence of aggressive behaviours and the predictive value of established correlates of aggression. Aggressive behaviours were common at baseline (61.6%) but only persistent in 30% of the sample over 10 years. Higher composite scores of overactivity and impulsivity at T1 were significantly associated with the persistence of aggressive behaviours at T2 (P = 0.027) and T3 (P = 0.012) with medium effect size. Aggressive behaviours are common in autism, but reduce with age.

Behavioural correlates of attention deficit hyperactivity disorder (ADHD) predict the presence and persistence of aggressive behaviour and as such may be useful clinical indicators to direct proactive intervention resources to ameliorate aggressive behaviours.