Risperidone is a powerful antipsychotic often prescribed to dementia patients who experience severe agitation or aggressive behavior. It is commonly used in care homes when non drug approaches fail to control distressing symptoms.

However, the study showed that dementia patients taking risperidone faced an increased risk of stroke even if they had no previous history of heart disease or stroke. This raises new concerns about how the medication is prescribed and monitored. Risperidone is currently the only drug of its kind licensed for use in dementia patients in the UK.

The results were published in the British Journal of Psychiatry and may lead to calls for changes in clinical practice.

Researchers Find Stroke Risk Consistent Across Patient Groups

One of the most striking findings was how evenly the stroke risk appeared across different types of patients.

“We knew Risperidone causes stroke, but we didn’t know whether some groups of people might be more at risk than others. We thought if we might identify characteristics that make people more at risk, doctors could avoid prescribing to patients with those characteristics,” said Dr. Byron Creese of Brunel University of London.

About half of all people living with dementia experience agitation, which can lead to severe distress for both patients and caregivers. When behavioral therapies and other non drug strategies fail, doctors may prescribe risperidone as a last resort.

These results highlight the difficult decisions faced by doctors and families. They must balance the drug’s ability to calm severe agitation against the potential for serious side effects such as stroke.

Limited Alternatives and Inconsistent Monitoring

Risperidone is often used to reduce aggression and severe agitation, but it is already known to carry a higher stroke risk for older adults. Despite this, there is still no dementia specific guidance on how doctors should monitor patients for these dangers.

Current NHS guidance recommends limiting risperidone treatment to six weeks when used for severe symptoms. In reality, many patients remain on the medication for longer periods. Monitoring practices can also vary across different parts of the country.

According to Dr. Creese, there are currently no licensed alternative drugs in the UK for treating severe agitation in dementia patients. Because of this, doctors must carefully explain the risks and benefits before prescribing it.

People who have already experienced a stroke are naturally more likely to suffer another one. If a stroke occurs after someone begins taking risperidone, the medication may not always be the sole cause. Doctors generally prescribe the drug only when other options have failed.

“These findings give clearer information about who is most at risk, which helps everyone make more informed choices. Every decision should be based on what is right for each person, through honest conversations between doctors, patients, and families,” said Dr. Creese.

How the Researchers Studied Stroke Risk

The research team examined anonymized NHS health records collected between 2004 and 2023. They compared dementia patients who were prescribed risperidone with similar patients who were not taking the drug.

Among people who had previously experienced a stroke, the annual rate per 1000 person years rose to 22.2 percent in those taking risperidone. In comparison, the rate was 17.7 percent among those who were not using the drug.

For patients with no previous stroke, the overall risk was lower but still noticeable. Stroke rates reached 2.9 percent for those taking risperidone compared with 2.2 percent among those who were not. The researchers also found that stroke risk was higher among patients using the medication for shorter periods (12 weeks).

“We hope that these data can be used in updated guidance that is more person centered and based on particular patient characteristics,” said Dr. Creese.