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Elevated psychiatric and substance use disorders in people with intellectual disabilities in a Swedish National Sample

Brown, Ruth C. ; Abrahamsson, Linda LU ; Sundquist, Jan LU ; Sundquist, Kristina LU and Kendler, Kenneth (2025) In Psychological Medicine 56.
Abstract

Background. Adults with intellectual disability (ID) experience marked mental health inequities, yet population-wide estimates that capture both primary- and specialist-care diagnoses remain scarce. Methods. Using nationwide Swedish registries, including primary care, specialist, inpatient, prescription drug, criminal, and suspicion registers, we included all individuals born in Sweden between 1958 and 1997 (N = 3,970,600), including 38,818 individuals with ID diagnoses (0.98%; 49.1% mild, 13.3% moderate, and 9.6% severe/profound). Hazard ratios (HR) were calculated using Cox proportional hazards regression to estimate the relative risk of lifetime diagnoses of major depression, anxiety disorders (ANX), obsessive-compulsive disorder... (More)

Background. Adults with intellectual disability (ID) experience marked mental health inequities, yet population-wide estimates that capture both primary- and specialist-care diagnoses remain scarce. Methods. Using nationwide Swedish registries, including primary care, specialist, inpatient, prescription drug, criminal, and suspicion registers, we included all individuals born in Sweden between 1958 and 1997 (N = 3,970,600), including 38,818 individuals with ID diagnoses (0.98%; 49.1% mild, 13.3% moderate, and 9.6% severe/profound). Hazard ratios (HR) were calculated using Cox proportional hazards regression to estimate the relative risk of lifetime diagnoses of major depression, anxiety disorders (ANX), obsessive-compulsive disorder (OCD), bipolar disorder (BD), attention-deficit/hyperactivity disorder (ADHD), drug use disorder, alcohol use disorder, schizophrenia, and other nonaffective psychosis. Additionally, cohort effects on psychiatric diagnosis risks in adults with intellectual disabilities versus the general population were evaluated. Results. People with ID were at higher risk for all psychiatric and substance use disorders, with HRs ranging from 1.7–2.0 for major depression and anxiety, drug and alcohol use disorders, 3.5–5.8 for BD, OCD and ADHD, and 10.9–12.7 for schizophrenia and other nonaffective psychosis. Higher prevalence was consistently seen among those with mild versus moderate or severe/profound intellectual disability. Relative risks narrowed modestly in successive birth cohorts, although absolute differences remained substantial. Conclusions. Across six decades of follow-up, adults with ID faced markedly higher psychiatric and substance-use morbidity-most pronounced for psychotic disorders-than the general population. Whole-system mental-health screening and tailored interventions are required to address this persistent disparity.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
epidemiology, health disparities, intellectual disability, population study, psychiatric disorders, registry data, substance use disorders
in
Psychological Medicine
volume
56
article number
e4
publisher
Cambridge University Press
external identifiers
  • pmid:41459592
  • scopus:105026221167
ISSN
0033-2917
DOI
10.1017/S0033291725102882
language
English
LU publication?
yes
additional info
Publisher Copyright: © The Author(s), 2025. Published by Cambridge University Press.
id
e2ad02ce-aab3-48b8-bc1d-255295e72b5b
date added to LUP
2026-02-10 14:54:05
date last changed
2026-05-06 04:22:56
@article{e2ad02ce-aab3-48b8-bc1d-255295e72b5b,
  abstract     = {{<p>Background. Adults with intellectual disability (ID) experience marked mental health inequities, yet population-wide estimates that capture both primary- and specialist-care diagnoses remain scarce. Methods. Using nationwide Swedish registries, including primary care, specialist, inpatient, prescription drug, criminal, and suspicion registers, we included all individuals born in Sweden between 1958 and 1997 (N = 3,970,600), including 38,818 individuals with ID diagnoses (0.98%; 49.1% mild, 13.3% moderate, and 9.6% severe/profound). Hazard ratios (HR) were calculated using Cox proportional hazards regression to estimate the relative risk of lifetime diagnoses of major depression, anxiety disorders (ANX), obsessive-compulsive disorder (OCD), bipolar disorder (BD), attention-deficit/hyperactivity disorder (ADHD), drug use disorder, alcohol use disorder, schizophrenia, and other nonaffective psychosis. Additionally, cohort effects on psychiatric diagnosis risks in adults with intellectual disabilities versus the general population were evaluated. Results. People with ID were at higher risk for all psychiatric and substance use disorders, with HRs ranging from 1.7–2.0 for major depression and anxiety, drug and alcohol use disorders, 3.5–5.8 for BD, OCD and ADHD, and 10.9–12.7 for schizophrenia and other nonaffective psychosis. Higher prevalence was consistently seen among those with mild versus moderate or severe/profound intellectual disability. Relative risks narrowed modestly in successive birth cohorts, although absolute differences remained substantial. Conclusions. Across six decades of follow-up, adults with ID faced markedly higher psychiatric and substance-use morbidity-most pronounced for psychotic disorders-than the general population. Whole-system mental-health screening and tailored interventions are required to address this persistent disparity.</p>}},
  author       = {{Brown, Ruth C. and Abrahamsson, Linda and Sundquist, Jan and Sundquist, Kristina and Kendler, Kenneth}},
  issn         = {{0033-2917}},
  keywords     = {{epidemiology; health disparities; intellectual disability; population study; psychiatric disorders; registry data; substance use disorders}},
  language     = {{eng}},
  month        = {{12}},
  publisher    = {{Cambridge University Press}},
  series       = {{Psychological Medicine}},
  title        = {{Elevated psychiatric and substance use disorders in people with intellectual disabilities in a Swedish National Sample}},
  url          = {{http://dx.doi.org/10.1017/S0033291725102882}},
  doi          = {{10.1017/S0033291725102882}},
  volume       = {{56}},
  year         = {{2025}},
}