Donate now See menu Shop Support line Search Home About dementia Types of dementia What is dementia? What is dementia? We explain what dementia is, including the causes and symptoms, and how it is diagnosed and treated. We also look at the different types of dementia. You are here: What is dementia? Symptoms of dementia What causes dementia? Who gets dementia? How can I tell if I have dementia? Diagnosing dementia Treatments for dementia Can dementia be prevented? What is dementia? Save this information Get a copy What is dementia? The word ‘dementia’ describes a set of symptoms that may include memory loss and difficulties with thinking, problem-solving or language. These changes are often small to start with, but for someone with dementia they have become severe enough to affect daily life. A person with dementia may also experience changes in their mood or behaviour. Press play to watch a two-minute video about dementia: Causes of dementia Dementia is caused when the brain is damaged by diseases, such as Alzheimer’s disease or a series of strokes. Alzheimer’s disease is the most common cause of dementia, but not the only one. The specific symptoms that someone with dementia experiences will depend on the parts of the brain that are damaged and the disease that is causing the dementia. What is the difference between dementia and Alzheimer's disease? If you’re not sure of the difference between dementia and Alzheimer’s disease, you’re not alone. We provide a simple explanation to understand the difference. Find out more Accessible versions of this information Watch a signed version of our information about dementia or listen to it in an audio version. Press play to listen: Press play to watch: We need your help People affected by dementia are facing the long-lasting effects of the pandemic. Reduced social contact and suspended support services had a devastating impact. We need your help now more than ever with donations to our Coronavirus Recovery Appeal. Make a monthly donation now Make a single donation now Need help finding dementia information? Find the information and support you're looking for with our free online tool. Get online support More practical and emotional support near you There are dementia services and support groups in your area. Find out what's available where you are. Previous Section You are on the first page Next Section 2. Symptoms of dementia Categories Alzheimer's disease, Dementia with Lewy bodies, Frontotemporal dementia (FTD), Mixed dementia, Young-onset dementia, Vascular dementia Further reading What kind of information would you like to read? Use the button below to choose between help, advice and real stories. Decide what you see My dad is in the final stages of mixed dementia and I hope he goes in peace Real stories Loraine adores her father, Martin, but says she has watched the progression of his mixed dementia for long enough. Loraine shares the emotional experience of her dad not recognising her, the challenges of non-verbal communication and other difficulties that the later stages of dementia can bring. 16 November 2021 34 Changes to Gran's routine during coronavirus really impacted her dementia Real stories India's grandmother, Brenda, has been a huge influence on her life and career path. India shares how the pandemic affected her gran, who has dementia with Lewy Bodies, and how the family continue to support Brenda since she moved into a care home. 04 October 2021 1 Husband’s young-onset Alzheimer’s diagnosis made me passionate about educating others Real stories Tracey Seymour, whose husband was diagnosed in his mid-50s, wants to challenge the perception that dementia only affects older people. 30 September 2021 4 Previous Next Sign up to get twice-monthly e-newsletter updates from Alzheimer’s Society. You can change what you receive at any time and we will never sell your details to third parties. Here’s our Privacy Policy. Useful links Jobs Working for us Contact us Publications and factsheets Training and conferences Blog Legal information Cookies Report a website problem Facebook Twitter Instagram Youtube All content © 2021 Alzheimer's Society. Registered office at Alzheimer's Society, 43-44 Crutched Friars, London, EC3N 2AE Alzheimer's Society is a registered Charity No. 296645. Registered as a company limited by guarantee and registered in England No. 2115499 We use some essential cookies to make this website work. We’d like to set additional cookies to understand how you use our site, remember your settings and assist our marketing to better support people affected by dementia. We also use cookies set by other sites to help us deliver services to you. Accept All Cookies Manage Cookies