OBJECTIVE: Previous studies suggest that cognitive and psychosocial impairments after subarachnoid hemorrhage (SAH) result from diffuse brain damage caused by the initial bleeding rather than from focal lesions. We describe the relationship of local infarctions to these impairments and explore how well test and questionnaire results explain psychosocial outcome. METHODS: A total of 170 patients, selected from a consecutive series of patients with aneurysmal SAH, underwent neurological and neuroradiological examinations, and 138 of them were assessed with neuropsychological tests and questionnaires 1 year after SAH. RESULTS: Patients with left and bilateral infarctions performed worse on verbal memory tests than the other patients, and patients with left infarctions had more impaired working capacity than those with no infarction. The indices of the severity of SAH were related to reductions in both working capacity and social activity but less clearly to poor test performances. Whereas the modified Rankin scale was the most important correlate of working capacity, performance on cognitive tests was associated with return to work, and questionnaire ratings of mental impairments correlated with reduced working capacity and decreased social activity. CONCLUSiON: Left-hemisphere infarctions cause deficits in verbal memory and working capacity. The severity of SAH is associated with impairments in working capacity and social activity rather than with specific cognitive deficits. Patients' and partners' opinions on patients' mental impairments could provide complementary information to clinical grades and cognitive tests in the evaluation of outcome after SAH.