['Although acute cocaine use has been temporally associated with aneurysmal subarachnoid hemorrhage (aSAH), the prevalence of vasospasm and the clinical outcome of patients experiencing aSAH associated with cocaine exposure are unclear. We have analyzed this patient population in our institution to address these issues.', 'Between 1992 and 1999, 440 patients presented to our institution with aSAH. This sample was retrospectively analyzed to determine which patients had used cocaine within 72 hours of aSAH as documented by urine toxicology studies or patient history. These patients were then compared with control aSAH patients without recent cocaine exposure through univariable and multivariable analyses.', 'Twenty-seven aSAH patients (6.1% of total) had either urine toxicology positive for cocaine metabolites (20 patients, 74%) or a history of cocaine use within 72 hours of aSAH (7 patients, 26%). Cocaine users were more likely to experience cerebral vasospasm defined as a delayed clinical deficit (from 3 to 16 days after aSAH) unexplained by concurrent CT scan and either responsive to hypervolemic and/or hypertensive therapy or accompanied by angiographic confirmation of vessel narrowing than control subjects (63% versus 30%; odds ratio [OR], 3.90; 95% confidence interval [CI], 1.77 to 8.62; P=0.001). Patients using cocaine were younger than control subjects (mean age, 36 versus 52 years; P<0.0001). Aneurysms of the anterior circulation were observed more frequently in cocaine users than in control subjects (97% versus 84%; OR, 6.89; 95% CI, 1.18 to 47.47; P=0.029). A significant difference was not observed, however, in the discharge Glasgow Outcome Scale (GOS) scores between the 2 groups (P=0.73). Differences were not observed between the 2 groups when the distributions of sex, hypertension, admission Glasgow Coma Scale subarachnoid hemorrhage grade, and multiple aneurysms were analyzed. Logistic regression models identified variables independently associated with vasospasm and discharge GOS score. Only a thick blood clot on the admission CT (OR, 7.46; 95% CI, 3.95 to 14.08; P<0.0001) and recent cocaine use (OR, 6.41; 95% CI, 2.14 to 19.23; P=0.0009) were independently associated with vasospasm. Cocaine use was not independently associated with the discharge GOS score.'] Is cocaine use an independent risk factor for cerebral vasospasm after aneurysmal subarachnoid hemorrhage?