Vascular dementia is caused by problems in the supply of blood to the brain, often due to conditions like strokes or mini-strokes. It is characterized by stepwise cognitive decline following vascular events and symptoms that overlap with Alzheimer's disease, though it often occurs at a younger age. Risk factors include age, history of strokes, high blood pressure, diabetes, smoking, and atrial fibrillation. Treatment focuses on controlling vascular risk factors and symptoms.