Insufficient blood supply to the brain may lead to insomnia and hypersomnia, but it is not the main cause of insomnia and hypersomnia. Insufficient blood supply to the brain may lead to poor blood circulation in the brain, and there may be vegetative nerve dysfunction, which may easily cause insomnia and excessive dreaming. Insufficient blood supply to the brain may also cause dizziness, forgetfulness, memory loss and other problems, which may also cause insomnia. Insufficient blood supply to the vertebral basilar artery may cause episodes of dizziness, nausea and vomiting. The causes of insomnia are mainly psychosocial factors, such as stress in life, unpleasant mood, shock, or depression, anxiety co-morbidities and other factors. Suffering from insomnia or cerebral blood supply insufficiency should go to the hospital in time, and standardized diagnosis and treatment under the guidance of professional physicians.