6th Edition of Neurology World Conference 2026

Abstract

Background Subarachnoid hemorrhage (SAH) mainly affects working‑age adults, and its impact often goes far beyond the initial hospital stay. Even though more patients now survive, we still lack good population‑level data on long‑term neuropsychiatric problems such as dementia, epilepsy, and mood disorders. It is also unclear how much delayed cerebral ischemia (DCI) – the most important secondary brain injury after SAH – contributes to these outcomes over several years. This study looked at how often these neuropsychiatric conditions develop after SAH and whether DCI raises that risk during five years of follow‑up. Methods We used the TriNetX Research Network (a large, multi‑institutional electronic health record database) for a retrospective cohort study. We identified adults with non‑traumatic SAH (ICD‑10 I60) diagnosed between 2013 and 2020 and excluded anyone with a prior neuropsychiatric diagnosis, so that all outcomes were truly new‑onset. DCI was defined by ICD‑10 codes for cerebral ischemia (I67.82) or vasospasm (I67.84) during the index hospitalization. We performed three separate 1:1 propensity score‑matched comparisons: SAH vs. matched controls (72,976 pairs), SAH with DCI vs. SAH without DCI (5,301 pairs), and SAH with DCI vs. matched controls (5,299 pairs). Incident outcomes – dementia (composite), epilepsy, depression, and anxiety – were tracked over five years using Kaplan‑Meier analysis and Cox proportional hazards models. Results Among 73,007 SAH patients, the risk of epilepsy was more than eleven times higher than in matched controls (RR 11.25, 95% CI 9.95–12.71), dementia risk was four times higher (RR 4.02, 95% CI 3.72–4.35), depression risk doubled (RR 2.08), and anxiety risk increased by about half (RR 1.51); all p<0.0001. DCI made these risks even worse. Compared to controls, patients with DCI had an 18‑fold higher epilepsy risk (RR 18.92, 95% CI 12.68–28.24), a seven‑fold higher dementia risk (RR 6.98, 95% CI 5.39–9.05), and nearly four times the risk of depression (RR 3.89). The five‑year cumulative probability of any neuropsychiatric event was 37.5% in the DCI group, 26.5% in SAH patients without DCI, and only 11.4% in controls (DCI vs. controls: HR 4.97, 95% CI 4.44–5.55, p<0.001). Importantly, the survival curves kept diverging over the entire five‑year period. Surgical clipping was linked to higher risks of epilepsy (RR 1.48, p<0.001) and dementia (RR 1.46, p=0.013) than endovascular coiling, but rates of mood disorders were similar between the two treatments. Conclusion SAH carries a heavy and progressive long‑term neuropsychiatric burden. DCI is the main driver of that risk, and the fact that the survival curves continue to separate over five years points to ongoing neurodegeneration rather than just a one‑time injury. These results suggest we should think of SAH as a chronic brain condition, not just an acute event. All survivors, especially those who had DCI, would benefit from structured long‑term neuropsychiatric follow‑up. Clinical guidelines need to address seizure prophylaxis, routine cognitive screening, and early psychiatric referral for this high‑risk population. Keywords: Subarachnoid hemorrhage; Delayed cerebral ischemia; Dementia; Epilepsy; Neuropsychiatric outcomes; Mood disorders; TriNetX; Propensity score matching