Frontotemporal dementia
Frontotemporal dementia is an uncommon form of dementia that damages the front and sides of the brain — the parts involved in personality, behaviour, language and planning. Unlike most dementias it usually starts younger, often between 45 and 65, and it is the most common form of dementia in people under 60. Memory is often unaffected at first. What changes instead is behaviour — acting out of character, losing motivation, losing the ability to read how other people feel — or language: speaking slowly, struggling to find words or to put them in order. Later there can be problems with concentration, with movement and with swallowing, and memory can be affected too. It is caused by a build-up of abnormal proteins inside brain cells, and it sometimes runs in families. Diagnosis usually involves tests of thinking and memory, blood tests and a brain scan, and it can take a long time to reach. There is no cure and no treatment that slows it down. Care is about managing symptoms and supporting the person and the people around them, through medicines for some symptoms, speech and language therapy, physiotherapy, memory cafés and support groups. It gets worse over time, and people live on average around eight to ten years after diagnosis, though that varies a great deal.
This is a plain summary, not medical advice, and it is not a substitute for talking to your GP or your clinical team. For NHS information about frontotemporal dementia, speak to your GP or call NHS 111.
People who have talked about it
1 story, each one written in our own words from what the person said publicly themselves.

Bruce Willis
Bruce Willis's family on his frontotemporal dementia diagnosis
Content note — this story covers a subject some people would rather choose when to read.
On 16 February 2023 Bruce Willis's family published a statement through the Association for Frontotemporal Degeneration, a charity whose work is supporting people affected by the disease and funding research into it. This story is written from that statement. They wrote that they had announced a diagnosis of aphasia in the spring of 2022, that his condition had progressed since then, and that there was now a more specific diagnosis: frontotemporal dementia. Difficulty with communication, they said, is only one of the symptoms he faces. They described the new diagnosis as painful, and at the same time as a relief, because it was finally a clear one. Much of the statement is about the disease rather than about him. They called it a cruel illness that many people have never heard of and that can happen to anyone. They noted that it is the most common form of dementia in people under 60, that reaching a diagnosis can take years, and that it is therefore probably far more common than the figures show. They wrote that there are no treatments for it today, and said they hope that changes. They were explicit about why they were making it public. They asked that any attention go towards awareness and research rather than towards him, and wrote that he had always used his voice to help other people and to raise awareness of things that mattered. If he could respond himself, they said, they believe he would want to bring attention to the disease and to connect with other people living with it. They pointed readers towards the charity for information and support. They ended by asking for compassion, understanding and respect, so that they can help him live as full a life as possible. Nothing here is medical advice, and nothing here is an update. The statement is from February 2023, and we have added nothing to it.
Photographs, in order: Bruce Willis by Gage Skidmore (CC BY-SA 3.0).