Long-term neuropsychiatric outcomes after aneurysmal subarachnoid hemorrhage: Seizure, dementia, and associations with delayed cerebral ischemia and treatment modality.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (aSAH), as a hemorrhagic stroke, accounts for approximately 5% of all strokes but disproportionately affects adults in their fourth and fifth decades during peak productive years, carrying a neuropsychiatric burden extending far beyond the acute event. Despite advances in neurovascular and surgical technique, long-term psychiatric and cognitive consequences of aSAH remain incompletely characterized. Delayed cerebral ischemia (DCI), occurring in 20-30% of survivors, has been proposed as a key neuropsychiatric driver, yet its independent contribution to seizure, dementia, and mood disorders beyond surgical treatment itself has not been quantified in large propensity-matched studies. Whether treatment modality differentially affects these outcomes also remains unresolved. We sought to determine five-year neuropsychiatric outcome rates in surgically confirmed aSAH and the independent contributions of DCI and surgical approach. METHODS: Retrospective cohort study using the TriNetX federated electronic health record network with five years of follow-up within 2013-2020. Adults with raptured aSAH confirmed by surgical treatment were identified. Three propensity-matched comparisons were performed: aSAH versus matched population controls; aSAH with DCI versus aSAH without DCI; and aSAH with DCI versus matched controls. A fourth comparison examined clipping versus coiling. Primary outcomes included incident seizure disorder, composite dementia, depression, and mood/anxiety disorders over five years, representing the dominant post-stroke chronic disease burden in hemorrhagic stroke survivors. RESULTS: Among 8231 aSAH patients, 2131 (25.9%) developed DCI; 2024 (24.6%) underwent surgical clipping and 6207 (75.4%) endovascular coiling. Compared with matched controls, aSAH was associated with significantly elevated risks of seizures (RR 13.87 [95% CI 9.65-19.94], p < 0.001), composite dementia (RR 3.62 [95% CI 2.80-4.68], p < 0.001), and depression (RR 2.19 [95% CI 1.89-2.53], p < 0.001). Within the aSAH cohort, DCI was associated with higher seizure risk (RR 1.43, p < 0.001), whereas associations with composite dementia and mood disorders did not reach statistical significance. Compared with matched controls, DCI patients faced markedly elevated seizure risk (RR 16.69 [95% CI 9.57-29.12], p < 0.001) and composite dementia risk (RR 4.58 [95% CI 3.01-6.97], p < 0.001). Surgical clipping was independently associated with higher seizure disorder (RR 1.48 [95% CI 1.19-1.83], p < 0.001) and composite dementia (RR 1.46 [95% CI 1.08-1.98], p = 0.013) risks versus coiling. Kaplan-Meier analysis demonstrated progressively diverging neuropsychiatric event curves over five years, with DCI patients carrying the highest cumulative burden (HR 2.55 versus controls, p < 0.001). CONCLUSIONS: aSAH carries a substantial and progressive long-term neuropsychiatric burden. DCI was associated with higher seizure risk, whereas associations with dementia and mood disorders did not reach statistical significance. Clipping was associated with higher seizure and composite dementia risks than coiling. These findings support long-term neuropsychiatric follow-up but require cautious interpretation because infarct characteristics, aneurysm location, and operative approach were unavailable. As a hemorrhagic stroke subtype with a distinct younger demographic profile, aSAH demands neuropsychiatric surveillance pathways currently absent from stroke care guidelines globally.