People with intellectual disabilities inappropriately prescribed antipsychotics

Large numbers of people with intellectual disabilities are being inappropriately prescribed antipsychotic drugs, according to new research.

The University College of London (UCL) study, published in the BMJ, found that antipsychotics were often prescribed to older people, or those who had dementia, autism or an intellectual disability.

Lead author of the study, Dr Rory Sheehan, said: “The number of people with intellectual disabilities who have been prescribed antipsychotics is greatly disproportionate to the number diagnosed with severe mental illness for which they are indicated.

“People who show problem behaviours, along with older people with intellectual disability or those with co-existing autism or dementia, are significantly more likely to be given an antipsychotic drug, despite this being against clinical guidelines and risking possible harm.”

The study looked at anonymised GP records of 33,016 UK adults with intellectual disabilities between 1999 and 2013 and found that over one-quarter had been prescribed antipsychotic drugs, of whom 71 per cent had no record of severe mental illness.

Intellectual disability is a lifelong condition that begins before the age of 18 and is characterised by limitations in intellectual functioning (generally indicated by an IQ under 70) and difficulties with one or more life skills.

The study has revealed that around one per cent of the British population has an intellectual disability.

Antipsychotic drugs are designed to treat severe mental illnesses such as schizophrenia, yet the research has found that there is very little evidence to suggest that they help to address behavioural problems in people with intellectual disability.

Behaviour problems that might be seen in people with intellectual disability include aggression, self-injury, destruction to property and other behaviours outside social norms.

However, the study has found that the rate of prescribing antipsychotic drugs to people with intellectual disability has fallen gradually but consistently over the past 15 years, indicating that alternative therapies are being utilised and GPs are changing their practice.

Other classes of prescribed drugs used to treat mental illness have also been prescribed to people with intellectual disability in large numbers. Drugs used to treat anxiety were the most frequently prescribed, followed by antidepressants.

Both of these types of drug were found to be given at substantially higher rates than mental disorders were recorded, suggesting that these drugs could also be prescribed inappropriately in some cases.

Side-effects of antipsychotic drugs include sedation, weight gain, metabolic changes that can ultimately lead to diabetes, and movement problems such as restlessness, stiffness and shakiness.

Dr Sheehan continued: “Side-effects can be managed, but the risks and benefits must be carefully considered before prescribing antipsychotics to people without severe mental illness.

“Research evidence does not support using antipsychotics to manage behaviour problems in people with intellectual disabilities. Many people with intellectual disability and behaviour disturbance have complex needs and other interventions, such as looking at the support people receive and their communication needs, should be prioritised.

“Antipsychotics, or indeed any medications, should not be prescribed lightly and are no substitute for comprehensive care.”