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


METHODS
Cohort study.


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


METHODS
33,016 adults (58% male) with intellectual disability who contributed 211,793 person years' data.


METHODS
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.
Division of Psychiatry, University College London, London W1T 7NF, UK r.sheehan@ucl.ac.uk.
Rory
R
Sheehan
Division of Psychiatry, University College London, London W1T 7NF, UK.
Angela
A
Hassiotis
Research Department of Primary Care and Population Health, University College London (Royal Free Campus), London NW3 2PF, UK.
Kate
K
Walters
Division of Psychiatry, University College London, London W1T 7NF, UK.
David
D
Osborn
Division of Psychiatry, University College London, London W1T 7NF, UK.
André
A
Strydom
Research Department of Primary Care and Population Health, University College London (Royal Free Campus), London NW3 2PF, UK.
Laura
L
Horsfall
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000188:drug therapy / Q000453:epidemiology*; D008297:Male; D001523:Mental Disorders / Q000188:drug therapy / Q000453:epidemiology*; D008875:Middle Aged; D015999:Multivariate Analysis; D010818:Practice Patterns, Physicians' / Q000639:trends; D055656:Prescriptions / Q000706:statistics & numerical data; D011619:Psychotropic Drugs / Q000627:therapeutic use*; D006113:United Kingdom / Q000453:epidemiology
D011619:Psychotropic Drugs