Dementia is a broad term describing a decline in cognitive function severe enough to interfere with daily life. It encompasses various disorders, including Alzheimer's disease, vascular dementia, and Lewy body dementia. Risk factors include age, genetics, and cardiovascular health. Symptoms may include memory loss, confusion, difficulty with language, and impaired reasoning. Diagnosis involves medical history, physical examination, and cognitive testing. While some causes of dementia are reversible, such as vitamin deficiencies or medication side effects, most are progressive and irreversible. Treatment focuses on symptom management, support for affected individuals and caregivers and addressing underlying health conditions. Early detection and intervention can improve outcomes.