A major change in personality in the elderly is usually a precursor to Alzheimer’s disease. The disease is a neurodegenerative disease that occurs mostly in older adults over the age of 60, with the incidence increasing significantly with age. Patients with the disease have a progressive onset, usually with an insidious onset, and most have a disease duration of 5-10 years. Patients mainly present with progressive intellectual decline and personality changes. In the early stages, patients may show a decline in near memory but a relative preservation of distant memory, and as the disease worsens, cognitive dysfunction may develop. In advanced stages, patients may experience complete loss of cognitive function, as well as personality changes or changes in personality. Patients may present as not recognizing their old friends, believing visitors to be burglars, often being frightened by their own images in the mirror, etc. Patients in advanced stages may generally require long-term care from others.