What is already known on this topic

Depression may be a direct cause of stroke.1 Alternatively, an observed association between depression and stroke may be generated by indirect processes when depression is not the immediate cause.1 Thus, depression, particularly if chronic or recurrent, could act as an upstream influence leading to increased stroke risk via intervening behaviours linked with low motivation such as smoking and lack of exercise. Further, a depression–stroke association could be spurious. A non-causal explanation likely accounted for findings from 24-year follow-up of the Whitehall II cohort.1 Depressive symptoms were linked robustly to the incidence of major acute coronary events, but the association with stroke was limited to the 5-year period after psychological assessment. Depression may thus be a prodromal symptom of stroke, perhaps of vascular origin, generated by subclinical changes to the brain before the …