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Mental illness, challenging behaviour, and psychotropic drug prescribing in people with intellectual disability: UK population based cohort study

BMJ 2015; 351 doi: (Published 01 September 2015) Cite this as: BMJ 2015;351:h4326
  1. Rory Sheehan, academic clinical fellow1,
  2. Angela Hassiotis, professor1,
  3. Kate Walters, senior clinical lecturer2,
  4. David Osborn, professor1,
  5. André Strydom, reader1,
  6. Laura Horsfall, senior research associate2
  1. 1Division of Psychiatry, University College London, London W1T 7NF, UK
  2. 2Research Department of Primary Care and Population Health, University College London (Royal Free Campus), London NW3 2PF, UK
  1. Correspondence to: Rory Sheehan r.sheehan{at}
  • Accepted 31 July 2015


Objectives To describe the incidence of recorded mental illness and challenging behaviour in people with intellectual disability in UK primary care and to explore the prescription of psychotropic drugs in this group.

Design Cohort study.

Setting 571 general practices contributing data to The Health Improvement Network clinical database.

Participants 33 016 adults (58% male) with intellectual disability who contributed 211 793 person years’ data.

Main outcome measures Existing and new records of mental illness, challenging behaviour, and psychotropic drug prescription.

Results 21% (7065) of the cohort had a record of mental illness at study entry, 25% (8300) had a record of challenging behaviour, and 49% (16 242) had a record of prescription of psychotropic drugs. During follow-up, the rate of new cases of mental illness in people without a history at cohort entry was 262 (95% confidence interval 254 to 271) per 10 000 person years and the rate of challenging behaviour was 239 (231 to 247) per 10 000 person years. The rate of new psychotropic drug prescription in those without a previous history of psychotropic drug treatment was 518 (503 to 533) per 10 000 person years. Rates of new recording of severe mental illness declined by 5% (95% confidence interval 3% to 7%) per year (P<0.001), and new prescriptions of antipsychotics declined by 4% (3% to 5%) per year P<0.001) between 1999 and 2013. New prescriptions of mood stabilisers also decreased significantly. The rate of new antipsychotic prescribing was significantly higher in people with challenging behaviour (incidence rate ratio 2.08, 95% confidence interval 1.90 to 2.27; P<0.001), autism (1.79, 1.56 to 2.04; P<0.001), and dementia (1.42, 1.12 to 1.81; P<0.003) and in those of older age, after control for other sociodemographic factors and comorbidity.

Conclusions The proportion of people with intellectual disability who have been treated with psychotropic drugs far exceeds the proportion with recorded mental illness. Antipsychotics are often prescribed to people without recorded severe mental illness but who have a record of challenging behaviour. The findings suggest that changes are needed in the prescribing of psychotropics for people with intellectual disability. More evidence is needed of the efficacy and safety of psychotropic drugs in this group, particularly when they are used for challenging behaviour.


  • Contributors: All authors developed the idea and method for the study, interpreted the results, and wrote the manuscript. LH did the data extraction and analysis. RS is the guarantor.

  • Funding: This work received funding from the Baily Thomas Charitable Fund (grant 518669) and the UK National Institute for Health Research (grant RP-DG-0611-10003). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at (available on request from the corresponding author) and declare: all authors had financial support from the Baily Thomas Charitable Fund and the UK National Institute for Health Research for the submitted work; AS has received research grants from the Wellcome Trust and acted as an investigator for Roche Pharmaceuticals; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: IMS Health has overall ethical approval to supply data to researchers. The study received approval from the THIN Scientific Review Committee (reference 14-071).

  • Data sharing: A full list of Read codes used and drugs included is available from the corresponding author.

  • Transparency declaration: The lead author (the manuscript’s guarantor) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

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