Personality disorders in people with learning disabilities: follow-up of a community survey.
Personality disorder in adults with ID foretells more medicines, clinic visits, and offending within five years.
01Research in Context
What this study did
Symons et al. (2005) followed adults with intellectual disability for five years. They wanted to know if having a personality disorder changed later health and service use.
The team tracked who got more medicines, more clinic visits, or police contact. They compared adults with and without a diagnosed personality disorder.
What they found
Adults with ID plus personality disorder needed more psychiatric drugs. They also saw doctors more often and had more trouble with the law.
The study shows personality disorder is a red flag for heavier service use later on.
How this fits with other research
Lotfizadeh et al. (2020) extends these results to kids. They found U.S. youth with ID use more mental-health services and medicines than peers, especially during school years.
Delprato (2002) is the forerunner. That review warned there were no good risk tools for offenders with ID. The new data answer the call: personality disorder itself predicts later offending.
Kennedy (2025) adds a possible driver. A 2025 review shows sleep loss spikes challenging behavior in people with ID. Poor sleep could partly explain the higher psychiatric drug use seen by J et al.
Why it matters
If you serve adults with ID, screen for personality disorder early. Mark these clients for closer watch on meds, sleep, and legal risk. Build in regular medication reviews and check sleep hygiene before raising doses. Share the risk picture with justice partners so everyone uses the same safety plan.
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02At a glance
03Original abstract
BACKGROUND: A sample of community-based service users with intellectual disability (ID) was re-examined after 5 years to determine the impact of a diagnosis of personality disorder (PD). METHODS: Seventy-five of the original 101 participants were followed up. Of these, 21 people had a PD identified during the original study. RESULTS: Compared with controls, people with a PD were significantly more likely to receive central nervous system (CNS) drugs, have more contact with psychiatric services, show increased offending behaviour, score higher on the Aberrant Behaviour Checklist and score above the threshold on the Psychiatric Assessment Schedule for Adults with Developmental Disability (PAS-ADD). Participants with PD recorded were more likely to have a recorded psychiatric disorder, have contact with specialist teams, and have more hospital admissions. CONCLUSION: People with ID and PD are able to live in the community with specialist support but improved assessment, diagnosis and support services need to be targeted more effectively to them.
Journal of intellectual disability research : JIDR, 2005 · doi:10.1111/j.1365-2788.2005.00762.x