BACKGROUND: The co-occurrence of stroke and psychosis is a serious neuropsychiatric condition but little is known about the course of this comorbidity. We aimed to estimate longitudinal associations between stroke and psychosis over 10 years. METHODS: A 10-year population-based study using data from the English Longitudinal Study of Ageing. A structured health assessment recorded (i) first-occurrence stroke and (ii) psychosis, at each wave. Each were considered exposures and outcomes in separate analyses. Logistic and Cox proportional hazards regression and Kaplan-Meier methods were used. Models were adjusted for demographic and health behaviour covariates, with missing covariates imputed using random forest multiple imputation. RESULTS: Of 19 808 participants, 24 reported both stroke and psychosis (median Wave 1 age 63, 71% female, 50% lowest quintile of net financial wealth) at any point during follow-up. By 10 years, the probability of an incident first stroke in participants with psychosis was 21.4% [95% confidence interval (CI) 12.1-29.6] compared to 8.3% (95% CI 7.8-8.8) in those without psychosis (absolute difference: 13.1%; 95% CI 20.8-4.3, log rank p < 0.001; fully-adjusted hazard ratio (HR): 3.57; 95% CI 2.18-5.84). The probability of reporting incident psychosis in participants with stroke was 2.3% (95% CI 1.4-3.2) compared to 0.9% (95% CI 0.7-1.1) in those without (absolute difference: 1.4%; 95% CI 0.7-2.1, log rank p < 0.001; fully-adjusted HR: 4.98; 95% CI 2.55-9.72). CONCLUSIONS: Stroke is an independent predictor of psychosis (and vice versa), after adjustment for potential confounders
