What is the likelihood of having a second subarachnoid hemorrhage?

Etiology dependent. This depends on the cause of your first subarachnoid hemorrhage. If it was aneurysmal, and the aneurysm was clipped or coiled and there are no others--then unlikely. This assumes you manage your blood pressure and there are no genetic risk factors.If it was traumatic and you suffer no further trauma-- unlikely. There are occasional subarachnoid hemorrhages where no cause is found.