Recreational substance use and aneurysmal subarachnoid hemorrhage: differential effects of alcohol and THC

Objective: The use of recreational drugs such as alcohol and tetrahydrocannabinol(THC) is increasing worldwide. While tobacco and certain illicit substances are well-established risk factors for aneurysmal subarachnoid hemorrhage (aSAH), the role of alcohol and THC remains less well defined. Understanding their potential impact on aneurysm rupture and clinical severity could have significant implications for prevention and patient management. This study aimed to investigate the influence of alcohol and THC use on the risk of intracranial aneurysm(IA) rupture and the clinical severity of aSAH. Methods: We prospectively included 954 patients with IA treated at a tertiary center in Germany between 2016 and 2023. Alcohol and drug use were documented through structured interviews. Risky alcohol use was defined as >20g/day(males) and >10g/day (females). Clinical severity of aSAH was assessed using the World Federation of Neurological Surgeons(WFNS) scale; radiographic severity was classified using the modified Fisher scale. Univariate and multivariate analyses were performed to evaluate associations between substance use, IA rupture, and severity. Results: Risky alcohol consumption was reported in 4.6% of patients, THC use in 5.3%, and polytoxicomania use in 3.2%. Risky alcohol consumption was independently significantly associated with IA rupture (adjusted odds ratio[aOR]2.00,95%,CI 1.07–3.75,p=0.031) and clinically severe aSAH (WFNS grade IV-V:aOR 3.26,95%,CI 1.34–7.95,p=0.009). No significant associations were observed for THC or polytoxicomania. Conclusions: Risky alcohol consumption was independently associated with the risk of IA rupture and more severe clinical presentation of aSAH. THC use showed no significant effect. Alcohol use should be actively addressed in IA patient counseling, and further studies are warranted to clarify the role of THC.