A large British study involving more than 165,000 dementia patients has revealed a hidden risk of stroke associated with risperidone, a drug commonly used to treat severe agitation. Researchers have found that this antipsychotic increases the risk of stroke in dementia patients in general, including those without a history of heart disease or stroke. These findings challenge the previous belief that some patients are safer candidates for treatment. Risperidone is the only drug of its type approved for the treatment of dementia. Doctors often use it as a last resort when symptoms like agitation become unmanageable.