High blood pressure. Most commonly high blood pressure (hypertension), which puts a toll on small brain blood vessels which can rupture and bleed, usually at older age. Other causes include brain aneurysms, vascular malformations, tumors, head injury, amyloid angiopathy, use of stimulants including street drugs, medications such as blood thinners, brain surgery, cerebral venous thrombosis etc.
Hypertension is # 1. Chronic high blood pressure, alcohol abuse, bleeding from existing vascular brain lesion, primary and metastatic cancers, cerebral vasculitis (inflammatory), coagulopathies (multiple causes), low platelet count, anticoagulants (coumadin (warfarin) etc), fibrinolysis, cocaine, amphetamines, cerebral malaria, and trauma. This list is not all inclusive, but includes many of the common causes.
Many causes. There could be a coagulation problem, certain blood thinning medications could predispose, congenital conditions such as an aneurysm, tumors, also trauma.
Berry aneurysm. A leaking berry aneurysm or arteriovenous malformation are the causes. Both are inherited conditions.
Many causes. Hemorrhagic stroke can happen from severe elevation in blood pressure (most common), or from an ischemic stroke transforming into a hemorrhagic, or a subarachnoid hemorrhage from a ruptured aneurysm, or from an AVM (arteriovenous malformation), or a large cortical brain hemorrhage from an amyloid angiopathy (in elderly with dementia) etc etc.
Diabetes. Diabetes is the most common that causes bleeding in the eye. It rarely causes bleeding in the brain. Patients with uncontolled hypertension are more prone to bleeding in the eye and brain-but this is problem occuring together is rare.