Severe mental illness may increase stroke risk, study suggests

Severe mental illness is linked to higher stroke risk in early and middle adulthood and increased dementia risk across adulthood, a study suggests.

An analysis of health records from nearly 700,000 people found significant associations between severe mental illness and both dementia and stroke.

The link with dementia was seen across every age group studied, while the increased risk of stroke was particularly marked in early and middle adulthood.

Michele De Prisco, co-lead author at Hospital Clínic-IDIBAPS and the University of Barcelona, said: “Although dementia remains rare in that 30 to 39 age group overall, the size of the difference associated with mental illness was notable.

“For every 100,000 people without a severe mental illness, about 24 had dementia at ages 30-39, compared with about 550 among those with a severe mental illness.”

“One of the most important contributions of our findings is to raise awareness that conditions such as dementia and stroke, which in clinical practice are often thought of as problems of old age, can also emerge in people who are much younger.

“That should put clinicians on alert.”

Researchers from Hospital Clínic-IDIBAPS and the University of Barcelona in Catalonia examined records from around 177,000 people diagnosed with schizophrenia, bipolar disorder or major depression and about 517,000 people without a psychiatric diagnosis.

They compared rates of dementia and stroke among people aged 20 to 99.

Adults aged 30 to 39 with severe mental illness had more than 20 times the odds of having dementia compared with those without a psychiatric diagnosis.

Dementia remained rare in this age group overall. About 550 in every 100,000 people with severe mental illness had dementia, compared with around 24 in every 100,000 people without severe mental illness.

Among adults aged 80 to 89, those with severe mental illness still had about four times the odds of dementia.

For stroke, people aged 40 to 49 with severe mental illness had nearly three times the odds of ischaemic stroke compared with those without a psychiatric diagnosis.

Mental illness affects around a billion people worldwide, while severe mental illness, including schizophrenia, bipolar disorder and major depression, affects at least 300m people.

The researchers said the findings support combining psychiatric care with regular monitoring of neurological and cardiovascular health.

De Prisco said: “These findings reinforce the need to think about severe mental illness as a whole-person health issue, not only a mental health diagnosis.

“What we are seeing is that risks linked to subsequent dementia and stroke may appear much earlier in life than many people expect, which means prevention, monitoring and coordinated care should also begin earlier.”

The study was cross-sectional, meaning it assessed health records at one point rather than following individuals over time. It can therefore show an association but cannot establish cause and effect.

De Prisco said: “Our next step is to set up longitudinal studies, where we follow individual patients over time.

“We also need to develop systems to integrate mental health and physical care, and then to test that these systems are effective.”

Kamilla Miskowiak, professor at the University of Copenhagen, who was not involved in the research, said: “These findings highlight the importance of considering cognitive and brain health as key treatment targets in people with severe mental illness.

“Cognitive impairment affects most people with schizophrenia and around half of individuals with bipolar disorder and major depression, often even when psychiatric symptoms are stable.

“The increased risks of dementia and stroke reported in this study emphasise the need to screen for cognitive decline and to identify and address modifiable risk factors, including cardiovascular health problems, as part of routine clinical care.

“While evidence-based interventions such as cognitive remediation can improve cognitive functions, there remains an urgent need for more effective treatments targeting cognition.

“Better integration of mental, cognitive, and physical health care could help improve both quality of life and long-term health outcomes for these patients.”