New Research Finds Heightened Stroke Risk Across All Dementia Patients Using Risperidone

LONDON — A landmark study involving more than 165,000 people has revealed that the antipsychotic drug risperidone increases the risk of stroke in all dementia patients, regardless of their prior health history. The findings, published in The British Journal of Psychiatry, challenge long-held clinical assumptions that certain “low-risk” patient groups might be shielded from the drug’s most severe side effects.

While risperidone has long carried warnings regarding cardiovascular events in the elderly, this new evidence suggests that the risk is universal. Even patients with no history of heart disease or previous strokes saw a statistically significant increase in stroke incidence after starting the medication. The study’s scale and duration (tracking data from 2004 to 2023) provide some of the most robust evidence to date, prompting calls for a nationwide review of how agitation in dementia is managed.

A Universal Risk: Breaking Down the Data

For years, clinicians hoped to identify a “safe” profile for prescribing risperidone—the only licensed antipsychotic in the UK for the management of severe aggression in Alzheimer’s disease. The hope was that by screening out patients with pre-existing cardiovascular issues, the benefits of the drug could be harnessed without the shadow of a stroke.

The data, however, tells a different story. Researchers from Brunel University London and the University of Exeter analyzed anonymized NHS records, comparing those prescribed risperidone with a matched control group.

Stroke Incidence Rates

While the absolute numbers are lower for those without a history of cardiovascular disease, the relative increase remains consistent. Notably, the risk was found to be highest during the first 12 weeks of treatment, a critical window that researchers say requires much more intensive monitoring than is currently standard practice.

The Clinician’s Dilemma: Balancing Calms and Consequences

Dementia is not just a disease of memory; for approximately 50% of patients, it involves periods of intense agitation, aggression, and distress. When “non-drug” interventions—such as sensory therapy, social engagement, or environmental adjustments—fail, caregivers and doctors often turn to risperidone as a last resort to ensure the safety of the patient and those around them.

“We knew risperidone caused stroke, but we didn’t know whether some groups of people might be more at risk than others,” said Dr. Byron Creese, a Senior Lecturer at Brunel University London and the study’s lead author. “We thought if we might identify characteristics that make people more at risk, doctors could avoid prescribing to patients with those characteristics. Our findings show that the risk is elevated across the board.”

This creates a harrowing choice for families. A stroke can lead to permanent disability or death, yet unmanaged severe agitation can lead to physical injury, caregiver burnout, and the breakdown of care home placements.

Gaps in Monitoring and Guidance

Despite the known dangers, there is currently no specific, standardized guidance within the NHS on how to monitor dementia patients for stroke symptoms once they begin a course of risperidone. While guidelines state that the drug should be used for the shortest time possible—usually capped at six weeks—real-world data suggests many patients remain on the medication for far longer.

Independent experts not involved in the study suggest this research should be a “wake-up call” for geriatric medicine.

“This study confirms that there is no ‘free lunch’ when it comes to using potent antipsychotics in a vulnerable elderly population,” says Dr. Elena Rossi, a consultant geriatrician (who was not involved in the research). “It underscores the necessity of the ‘start low, go slow’ mantra, but also highlights that we need to be much more vigilant in the first three months of prescription.”

Implications for Public Health and Caregivers

The study does not suggest an immediate, blanket ban on risperidone, as there are currently no UK-licensed alternatives for treating severe aggression in dementia. Instead, it advocates for a shift toward “person-centered” medicine and radical transparency.

What this means for families:

• Informed Consent: Before starting risperidone, doctors should have a detailed conversation with families about the stroke risk, even if the patient has a “healthy” heart.

• Short-term Use: The 12-week risk peak suggests that the current six-week limit is a vital safeguard that should be strictly enforced.

• Vigilance: Caregivers should be educated on the FAST (Face, Arms, Speech, Time) signs of stroke, particularly when a new medication is introduced.

Dr. Creese emphasizes that the goal is better communication: “Every decision should be based on what is right for each person, through honest conversations between doctors, patients, and families.”

Looking Forward: The Need for Alternatives

The findings are expected to reignite the debate over the “chemical cosh”—the perceived over-reliance on sedating medications in care settings. With the stroke risk now proven to be universal, the pressure is on the medical community to fast-track research into non-pharmacological treatments and safer drug alternatives.

As the global population ages and dementia rates climb, the need for a management strategy that doesn’t trade mental calm for physical catastrophe has never been more urgent.

References

• Primary Study: Choma, J., Griffiths, A., Henley, W., et al. (2025). Risk of stroke associated with risperidone in dementia with and without comorbid cardiovascular disease: population-based matched cohort study. The British Journal of Psychiatry. DOI: 10.1192/bjp.2025.10419.

Medical Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to your treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.