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Antipsychotic initiation among adults with intellectual and developmental disabilities in Ontario: a population-based cohort study
  1. Tara Gomes1,2,3,4,
  2. Wayne Khuu2,
  3. Mina Tadrous1,2,3,
  4. Simone Vigod2,4,5,6,
  5. Virginie Cobigo2,7,
  6. Yona Lunsky2,5,8
  1. 1Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
  2. 2ICES, Toronto, Ontario, Canada
  3. 3Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
  4. 4Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, Canada
  5. 5Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
  6. 6Department of Psychiatry, Women’s College Hospital, Toronto, Ontario, Canada
  7. 7Department of Psychology, University of Ottawa, Ottawa, Ontario, Canada
  8. 8Azrieli Adult Neurodevelopmental Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
  1. Correspondence to Tara Gomes; gomest{at}


Objectives To describe factors associated with initiating antipsychotics and patterns of persistence to antipsychotic therapy in a large cohort of adults with intellectual and developmental disabilities.

Design Population-based cohort study.

Setting Ontario, Canada.

Participants Adults with intellectual and developmental disabilities (IDD) in Ontario.

Outcome measures We used multivariable logistic regression to investigate patient characteristics associated with antipsychotic initiation. Patient characteristics studied included sociodemographic characteristics, measures of clinical comorbidity and health service use.

Results Among 39 244 individuals eligible for this study, 6924 (17.6%) initiated an antipsychotic over the accrual window, of whom 1863 (26.9%) had no psychiatric diagnosis in the prior 2 years. A number of factors were significantly associated with antipsychotic initiation, including male gender, residence in a group home, prior use of benzodiazepines, antidepressants or cognitive enhancers, a recent emergency department visit or mental health hospitalisation and a visit to a psychiatrist or family physician in the prior 90 days. In a secondary analysis, the association between antipsychotic initiation and age, prior diagnosis of diabetes or myocardial infarction and polypharmacy differed slightly on the basis of whether an individual had a previously diagnosed psychiatric disorder.

Conclusions Factors associated with the initiation of an antipsychotic differ according to the presence of a psychiatric diagnosis. Given the long duration of antipsychotic use in this population, future research is needed to understand the appropriateness of antipsychotic initiation among adults with IDD and the safety implications of long-term use of these products.

  • antipsychotic agents
  • developmental disabilities
  • pharmacoepidemiology

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  • Contributors TG was responsible for conception and design of the study, data acquisition and interpretation and drafting of the manuscript. WK was responsible for design of the study, data acquisition, analysis and interpretation and critical revisions of the manuscript. MT, SV and VC were responsible for design of the study, data interpretation and critical revisions of the manuscript. YL was responsible for conception and design of the study, data acquisition and interpretation and drafting of the manuscript. All authors provided final approval of the manuscript.

  • Funding This study was funded by grants from the Province of Ontario. It was also supported by ICES, which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC). We would like to thank IMS Brogan Inc for use of their Drug Information Database. Parts of this material are based on data and information compiled and provided by the Canadian Institute for Health Information (CIHI).

  • Disclaimer The opinions, results and conclusions reported in this paper are those of the authors and are independent from the funding source and those of CIHI. No endorsement by ICES, the Ontario government, or CIHI is intended or should be inferred.

  • Competing interests None declared.

  • Ethics approval This study was approved by the research ethics board of Sunnybrook Health Sciences Centre, Toronto and conducted at ICES in Toronto, Canada using deidentified data.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement The data set from this study is held securely in coded form at ICES. While data sharing agreements prohibit ICES from making the data set publicly available, access may be granted to those who meet prespecified criteria for confidential access, available at The full data set creation plan and underlying analytic code are available from the authors upon request, understanding that the programmes may rely on coding templates or macros that are unique to ICES.

  • Patient consent for publication Not required.

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