Can changing the medicines we prescribe improve autistic people's health?

Autistic people often have more health problems and a shorter life expectancy than non-autistic people. Healthcare differences may be a reason for this.

For example, medicines that alter mood and brain function are often prescribed to autistic adults and side effects from these could be contributing to health problems, such as high cholesterol.

On the other hand, once autistic adults have a health condition like high cholesterol, appropriate medication might not be prescribed quickly enough or be at the optimal dose.

As well as healthcare, there may be genetic reasons autistic people are more susceptible to diseases like heart disease and stroke. Some autistic people may also have genetic differences that mean certain types of medicine need to be prescribed at higher or lower doses for them.

Understanding these genetic differences could help healthcare professionals provide better care for autistic people, and reduce the number of health problems they have.

Project aims

The aim of our project is to find out if over-prescribing or under-prescribing some types of medicine, or genetic variations, cause health problems for people with autism.

We plan to:

• Compare how often healthcare professionals prescribe medicines that alter mood, and medicines that lower the risk of heart attack and stroke, to autistic adults compared with non-autistic adults
• Find out whether autistic adults are more likely to have side effects from these medicines than non-autistic adults
• Look at whether many autistic people have genetic variations that mean these drugs need to be prescribed at higher or lower doses than average
• Look for genetic reasons that autism and conditions like heart disease and stroke could be linked

Aws Sadik is performing this research for his PhD.

Our work so far

We compared antidepressant prescribing rates in autistic and non-autistic adults between 1997 and 2023. We used UK primary care records from the Clinical Practice Research Datalink (CPRD) to do this.

Our comparison included autistic adults (with and without intellectual disabilities) and non-autistic adults matched for year of birth, sex and cohort entry year. We reviewed:

• Prescribing rates
• Numbers of new prescriptions
• How long people were treated for
• Doses for selective serotonin reuptake inhibitors (a common antidepressant)
• Reasons for prescribing

Our analysis found that antidepressant use has increased in both autistic and non-autistic adults over time. However, this increase is sharper among autistic adults. By 2023, autistic adults were over three times more likely to be prescribed an antidepressant as age- and sex-matched non-autistic adults. They were also more likely to receive higher SSRI doses and remain on treatment for longer. Prescribing rates were highest among autistic adults without intellectual disability, but long-term prescribing was higher among autistic adults with intellectual disability.

Higher prescribing rates may reflect higher levels of anxiety and depression in autistic adults, and increases over time may be partly explained by changes in diagnostic practice. However, more research is needed to understand why autistic adults are more likely to receive long-term antidepressant treatment and whether current prescribing patterns are delivering the best outcomes for patients.