Alzheimer's disease is a neurodegenerative disorder that is the most common cause of dementia in older adults. It involves memory loss, confusion, and changes in behavior and personality. The disease progresses slowly over many years, affecting brain functions such as memory, language, and decision-making. Alzheimer's can lead to severe mental decline, dependency on others for care, and ultimately death. Risk factors include age, genetics, and lifestyle choices. While there is no cure, treatments are available to manage symptoms and improve quality of life.