Abstract
BackgroundAggressive behaviours are common inpeople with neurodevelopmental conditions,contributing to poorer quality of life and placementbreakdown. However, there is limited empiricalresearch documenting the prevalence and persistenceof aggressive behaviours in autism. In thislongitudinal study, aggressive behaviours wereinvestigated in a sample of autistic individuals over10years.MethodsCaregivers of autistic individuals, both withand without intellectual disability, completedquestionnaires relating to the presence of aggressivebehaviours atT1[N=229, mean age in years11.8,standard deviation (SD)5.9],T2(T1+3years,N=81, mean age in years15.1,SD5.9) andT3(T1+10years,N=54, mean age in years24.5,SD8.1). Analyses examined the presence and persistenceof aggressive behaviours and the predictive value ofestablished correlates of aggression.ResultsAggressive behaviours were common atbaseline (61.6%) but only persistent in30% of thesample over10years. Higher composite scores ofoveractivity and impulsivity atT1were significantlyassociated with the persistence of aggressivebehaviours atT2(P=0.027) andT3(P=0.012) withmedium effect size.ConclusionsAggressive behaviours are common inautism, but reduce with age. Behavioural correlates ofattention deficit hyperactivity disorder(ADHD) predict the presence and persistence ofaggressive behaviour and as such may be usefulclinical indicators to direct proactive interventionresources to ameliorate aggressive behaviours.Keywordsaggressive behaviours, autism,impulsivity, overactivity, persistence, prevalenceBackgroundThe term‘aggressive behaviours’is a broad term thatencompasses behaviours that inflict social, emotionaland physical harm (Farmer & Aman2011). In thiscontext, the term is not intended to imply that theperson showing the behaviour is intending to hurtanother person, but simply that these kinds ofbehaviours have the potential to cause harm. Physicalaggression is common and predicts deleteriousoutcomes for individuals with neurodevelopmentalconditions such as autism (Fitzpatricket al.2016),including an increased likelihood of admission toresidential facilities, physical abuse from caregivers,caregiver burnout, isolation and lower quality of life(Lakin1983; Stormshaket al.1999; Stithet al.2009;1Correspondence: Dr Catherine Laverty, School of Psychology,University of Birmingham,52Pritchatts Road, Edgbaston,Birmingham B15 2TT, UK (e-mail:c.laverty@bham.ac.uk).Journal of Intellectual Disability Researchdoi: 10.1111/jir.13004VOLUME PART©2023The Authors. Journal of Intellectual Disability Research published by MENCAP and International Association of theScientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License,which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial andno modifications or adaptations are made.bs_bs_banner