The findings come from a new INTERSTROKE study, published in Neurology, the medical journal of the American Academy of Neurology.INTERSTROKE is a global study of 26,877 adults with an average age of 62, across 32 countries including participants in Europe, Asia, North and South America, the Middle East and Africa.

Participants with stroke were matched to controls who had not suffered a stroke, but were similar in age, gender, racial or ethnic identity.

Robert P Murphy was the study author and consultant Stroke Physician and researcher at the College of Medicine, Nursing and Health Sciences at University of Galway.

Dr Murphy said: “Depression affects people around the world and can have a wide range of impacts across a person’s life. Our study provides a broad picture of depression and its link to risk of stroke by looking at a number of factors including participants’ symptoms, life choices, and antidepressant use. Our results show depressive symptoms were linked to increased stroke risk and the risk was similar across different age groups and around the world.”

The INTERSTROKE study found:

Of study participants, 18% of those who had a stroke had symptoms of depression compared to 14% of controls who did not have a stroke.

After adjusting for age, sex, education, physical activity and other lifestyle factors, people with depressive symptoms before stroke had a 46% increased risk of stroke compared to those with no depressive symptoms.

The more symptoms of depression participants had, the higher their risk of stroke.

Participants who reported five or more depressive symptoms had a 54% higher risk of stroke than those with no symptoms.

Those who reported three to four depressive symptoms and those who reported one or two symptoms of depression had 58% and 35% higher risk, respectively.

While people with symptoms of depression were not more likely to have more severe strokes, they were more likely to have worse functional outcomes one month after the stroke than those without depressive symptoms.

Professor Martin O’Donnell, Professor of Neurovascular Medicine at University of Galway and Consultant Stroke Physician at Galway University Hospitals, co-led the international INTERSTROKE study in partnership with Professor Salim Yusuf from the Population Health Research Institute at McMaster University, Canada.

Professor O’Donnell said: “The goal of INTERSTROKE is to better understand the importance of risk factors for stroke in different regions of the world and impact of stroke. In the INTERSTROKE study we have previously examined the roles of hypertension, alcohol, lipids and psychosocial stress as global determinants of stroke risk. The current analysis provides deeper insights into the association of depressive symptoms with stroke risk, reporting an increased risk. These analyses suggest that effective identification and management of depression may also be associated with reduce stroke risk, although the observational nature of the study does not permit definitive conclusions.”