Association of aggressive behaviours with psychiatric disorders, age, sex and degree of intellectual disability: a large-scale survey.
Psychiatric label predicts aggression type in ID—bipolar or impulse-control means watch everything; autism means watch physical and self-hit.
01Research in Context
What this study did
Hattier et al. (2011) asked staff at 1,000 agencies to fill out a survey on 4,069 clients with intellectual disability.
They listed each client’s psychiatric diagnosis and counted four kinds of aggression: hitting others, hitting objects, hitting self, and verbal threats.
The goal was to see which disorders go with which type of aggression.
What they found
Impulse-control and bipolar disorders were tied to every kind of aggression.
Autism was linked mainly to physical acts: hitting people, breaking things, and self-hitting.
Age, sex, and level of disability mattered, but the psychiatric label carried the strongest signal.
How this fits with other research
Diemer et al. (2023) followed autistic youth for ten years and found most aggression fades by adulthood. Their long view extends A’s snapshot, showing the autism-aggression link often weakens over time.
Hatzell et al. (2026) add another layer: poor sleep boosts aggression odds by a large share in autism. This suggests sleep screens may catch risk even when no mood or impulse-control diagnosis exists.
van der Miesen et al. (2024) meta-analysis shows caregiver-run SIB treatments work as well as clinic ones. While A mapped who hits self, R shows families can safely reduce that behavior at home.
Why it matters
Use the study like a quick triage guide. If a new client has both ID and bipolar or impulse-control disorder, plan for multi-form aggression. If the client carries only an autism label, watch for physical and self-hitting, but also screen sleep and track change—many kids will improve. Pair these odds with caregiver-based interventions shown by later work; they are cheap, strong, and can start Monday.
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02At a glance
03Original abstract
BACKGROUND: The link between aggression and mental disorders has been the focus of diverse studies in persons with and without intellectual disabilities (ID). Because of discrepancies in the finding of studies in persons with ID to date, and because of differences in research design, instruments used and the population studied, more research is needed. The purpose of this study was to delineate any significant association between certain psychiatric disorders and specific domains of aggressive behaviours in a large sample of persons with ID controlling for sex, age, autism and degree of ID. METHOD: Data from the present study were obtained from 47% of all persons with ID receiving services from New York State agencies, using the Institute for Basic Research - Modified Overt Aggression Scale (IBR-MOAS between 2006 and 2007). The IBR-MOAS was completed by the chief psychologists of 14 agencies based on information from the participants' files. Demographic information obtained included the psychiatric diagnosis made by the treating psychiatrist as well as information on age, sex and degree of ID. Data from 4069 participants were analysed. RESULTS: Impulse control disorder and bipolar disorder were strongly associated with all five domains of aggressive behaviour in the IBR-MOAS. Psychotic disorder was highly associated with four domains except for physical aggression against self (PASLF), which was of borderline significance. Anxiety was most associated with PASLF and verbal aggression against self (VASLF); depression with VASLF; obsessive compulsive disorder with physical aggression against objects (PAOBJ); personality disorders with verbal aggression against others (VAOTH), VASLF and PASLF; and autism with physical aggression against others (PAOTH), PAOBJ and PASLF. Mild to moderate ID was associated with VAOTH and VASLF and severe to profound ID with PAOBJ and PASLF. Female sex was most associated with VASLF. CONCLUSIONS: Impulse control, mood dysregulation and perceived threat appear to underlie most of the aggressive behaviours reported. Psychosis and depression appeared to have been over-diagnosed in persons with mild to moderate ID and under-diagnosed in persons with severe and profound ID. These findings replicate and extend findings from previous studies. The pattern of associations reported can be used as helpful indicators by professionals involved in the treatment of aggressive behaviours in persons with ID.
Journal of intellectual disability research : JIDR, 2011 · doi:10.1111/j.1365-2788.2011.01418.x