Insufficient blood supply to the brain in adolescents may be related to congenital malformations of the arteries, bad lifestyle habits, immune-related diseases and other causes. 1. Congenital malformation of arteries: such as missing vertebral artery, thin carotid artery, smog disease and other arterial malformations, which will affect the blood transportation of the head, and may appear dizziness and other symptoms of insufficient blood supply to the brain. 2. Bad life habits: such as staying up late, playing cell phone with head down or excessive study pressure may cause cerebral vascular spasm and narrowing, which may lead to dizziness and other phenomena of insufficient cerebral blood supply in adolescents. 3. Immune-related diseases: If immune-related diseases lead to vasculitis or central nervous system vasculitis and other diseases, it may lead to narrowing of blood vessels, and symptoms related to insufficient blood supply to the brain may appear. It is recommended that adolescents with cerebral blood supply insufficiency go to regular hospitals in time to clarify the cause of the disease and standardize the treatment under the guidance of doctors.