The main difference between dementia and Alzheimer's disease is the fact that dementia is a symptom of many diseases, including Alzheimer's, and Alzheimer's is a disease, according to Healthline. In addition to Alzheimer's disease, dementia may be caused by Parkinson's disease, Huntington's disease and the human immunodeficiency virus.
Dementia impacts the areas of the brain that affect memory and reasoning, states Healthline. It disables individuals to the point where they are no longer able to live independently, which affects their families emotionally and financially. Dementia begins with forgetfulness and progresses into confusion and severe forgetfulness in the form of poor hygiene and being unable to remember familiar names and faces. About 50 to 70 percent of individuals suffering from dementia have Alzheimer's disease.
Alzheimer's is a progressive disease that exists within the brain and worsens the longer an individual has it, explains Healthline. On average, symptoms, such as dementia, begin appearing after the age of 60, but the disease begins damaging the brain years prior. The disease causes cells within the brain to disconnect before they eventually die. While Alzheimer's disease may take much longer to become fatal in younger individuals, those diagnosed past age 80 may not survive past three years.