The proportion of people with intellectual disability in the UK who have been treated with psychotropic drugs far exceeds the proportion with recorded mental illness, a new study has found. This suggests that, in some cases, these drugs are being used to manage other presentations, such as challenging behaviour, rather than for mental illness, say the researchers. They call for changes in the prescribing of psychotropic drugs for people with intellectual disability as well as more evidence on their safety in this group.
People with intellectual disability develop severe mental illness at higher rates than do the general population and may show challenging behaviour. Concern has existed for many years that psychotropic drugs in general – and anti-psychotics in particular (mainly used to treat schizophrenia and bipolar disorder) – are overused in people with intellectual disability, but accurate estimates have been difficult to obtain. So a team of researchers based at University College London set out to describe rates of recorded mental illness, challenging behaviour, and use of psychotropic drugs in people with intellectual disability in UK primary care.
They analysed data from 571 UK general practices using the The Health Improvement Network (THIN), a large database of electronic health records, and identified 33,016 people with a record of intellectual disability. Average age at study entry was 36 years and average follow-up was five and a half years.
Of 9,135 participants treated with anti-psychotic drugs by the end of the study period, 6,503 (71%) did not have a record of severe mental illness. Of the 11,915 with a record of challenging behaviour, 5,562 (47%) had received anti-psychotic drugs, whereas only 1,561 (13%) had a record of severe mental illness. And of those with a record of prescription of anti-psychotics, 26% did not have a record of severe mental illness or challenging behaviour.
New prescriptions for anti-psychotics were significantly more common in older people and in those with a record of challenging behaviour, autism, dementia, and epilepsy, as well as mental illness. People with a record of challenging behaviour were more than twice as likely to receive a prescription for anti-psychotics compared with those without a record of challenging behaviour, say the authors.
Prescription of anti-psychotic drugs is disproportionate to the level of recorded severe mental illness and is associated with the presence of challenging behaviour, older age, and diagnoses of autism and dementia, they add.
“Inappropriate use of drug treatment has implications for the individual and for healthcare systems,” they warn. “These findings highlight the need for an improved evidence base for use of drugs and optimisation of drug treatment in people with intellectual disability.”
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.