Brain atrophy refers to a type of neuropsychiatric disease caused by organic lesions in the brain tissue itself due to various reasons, resulting in atrophy. Brain atrophy includes pediatric brain atrophy and adult brain atrophy. It is more common in the elderly. This disease occurs in adults: it mostly occurs in people over 50 years old, the course of the disease can be several years to decades, and it is more common in men than in women. Brain atrophy includes diffuse brain atrophy (including cortical atrophy, cerebellar atrophy, and atrophy of the cortex, cerebellum, and brainstem) and localized brain atrophy (more common after localized brain organic lesions such as trauma, vascular disease, and localized intracranial infection).