Dementia is the general term for a group of brain disorders that causes problems with thinking, memory, and behavior severe enough to interfere with daily activities of life. Alzheimer's disease is the most common cause of dementia, followed by multi-infarct dementia, which is caused by a series of strokes. Some of the other diseases that cause dementia are Creutzfeldt-Jakob disease, normal pressure hydrocephalus, Pick's disease, Parkinson's disease, Lewy body disease, and Huntington's disease. Symptoms of dementia may also be caused by depression, drug interaction, metabolic disorders (such as thyroid problems), head injury, vision or hearing problems, tumors, and infection. Getting a diagnosis of what is causing dementia symptoms is important because some of these conditions are reversible with the right treatment. Although Alzheimer’s is not reversible, the correct diagnosis helps you get treatments to help with symptoms and quality of life