Long-Term Neuropsychiatric Outcomes After Nontraumatic Subarachnoid Hemorrhage: The Critical Role of Delayed Cerebral Ischemia

Background Nontraumatic subarachnoid hemorrhage (SAH) often affects young adults, and survivors face long-term neuropsychiatric problems. We sought to determine the rate of neuropsychiatric outcomes and the impact of delayed cerebral ischemia (DCI) on these sequels. Methods Retrospective cohort study using TriNetX with five years follow up within 2013–2020. Adults with nontraumatic SAH were identified and propensity score matching was used across SAH without DCI, SAH with DCI, versus matched controls. Results Among 73,007 patients, those with SAH had a significantly increased risk of epilepsy (RR 11.25 [95% CI 9.95–12.71], p < 0.0001) and composite dementia (RR 4.02 [95% CI 3.72–4.35], p < 0.0001) compared to controls. DCI was associated with elevated risks of epilepsy (RR 18.92 [95% CI 12.68–28.24], p < 0.0001) and composite dementia (RR 6.98 [95% CI 5.39–9.05], p < 0.0001) versus controls. Clipping was associated with higher epilepsy (RR 1.48 [95% CI 1.19–1.83], p < 0.001) and dementia (RR 1.46 [95% CI 1.08–1.98], p = 0.013) compared to coiling. Survival analysis demonstrated worse neuropsychiatric event-free survival among SAH patients with DCI (HR 4.97 [95% CI 4.44–5.55], p < 0.001) compared to controls. Conclusions These findings demonstrate that SAH, particularly when complicated by DCI, is associated with substantially increased long-term risks of epilepsy and dementia, with clipping conferring additional epilepsy risk.