The Care CompassFrontotemporal Dementia Explained: Why It's Often Mistaken for Something Else First
This guide covers a specific, less-talked-about type of dementia. If you're looking for signs and symptoms of dementia more broadly, our Diagnosis & Understanding stage guide is the better place to start.
Why this one gets missed so often
Frontotemporal dementia (FTD) isn't rare, but it's rarely the first thing anyone thinks of. It's actually the most common cause of dementia diagnosed before the age of 65, and the third most common form of dementia overall, after Alzheimer's disease and Lewy body dementia. Despite that, families often spend months, sometimes years, being told it's stress, depression, a midlife crisis, or a relationship problem, because the first symptoms usually don't look like dementia at all.
What frontotemporal dementia actually is
FTD is caused by damage to the frontal and temporal lobes of the brain, the areas involved in personality, behaviour, decision-making and language. Unlike Alzheimer's, where memory loss usually comes first, FTD tends to affect who someone is and how they communicate well before it affects what they remember. Memory often stays relatively intact for a long time, which is one of the main reasons it doesn't get recognised as dementia straight away.
The typical age of onset is around 58, and onset before 40 or after 75 is relatively unusual, which is part of why it sits so closely alongside our guide on young-onset dementia.
The two main types, and why they look so different
FTD isn't one single pattern. Roughly half of cases are what's called the behavioural variant, and the other half fall under a group known as primary progressive aphasia. Knowing which one you're dealing with matters, because they can look completely different from the outside.
Behavioural variant FTD (bvFTD)
The most common type. Changes show up in personality, behaviour and social conduct first — things like acting out of character, losing social tact, changes in eating habits (often craving sweet food or overeating), poor decision-making, or seeming to lose empathy or awareness that anything has changed. Because these can look like a personality change, a mental health issue, or even a mid-life crisis, this is often the variant that takes longest to correctly identify.
Semantic dementia (a type of primary progressive aphasia)
A gradual loss of the meaning of words and things. Someone may still speak fluently and grammatically, but increasingly lose the underlying meaning — struggling to understand a familiar word, recognise a familiar face, or grasp what an everyday object is for. As it progresses, behavioural changes similar to bvFTD often start to appear too.
Non-fluent variant primary progressive aphasia
Difficulty with the physical act of speaking — effortful, halting speech, getting words in the wrong order, or struggling with grammar — even though the person still understands what's being said to them and knows what they want to say.
Logopenic variant primary progressive aphasia
Mainly word-finding difficulty and hesitant speech. This variant is a bit different from the other two language variants: it's more often linked to Alzheimer's disease pathology underneath, even though it presents as a language problem first.
Why diagnosis takes so long
Because the earliest signs are personality, behaviour or language changes rather than memory loss, FTD is very commonly mistaken for depression, anxiety, a stress reaction, or a relationship or workplace conflict, especially given how much younger the person often is compared to the popular idea of "getting dementia." If a GP hasn't seen it before, it doesn't always get considered early. If changes in personality, behaviour or speech don't feel like they add up to an existing explanation, it's entirely reasonable to ask directly for a referral to a neurologist or a specialist memory service.
Is it genetic?
Sometimes, but not usually. Around a third of cases run in families, most commonly linked to changes in one of three genes. The majority of people diagnosed with FTD, though, have no known family history at all. If FTD does run in your family, genetic counselling is available and worth asking a specialist about directly.
What support actually looks like
There's currently no cure and no medication that treats FTD itself, though some symptoms, particularly agitation or low mood, can sometimes be helped with careful, specialist-guided treatment. Speech and language therapy can support communication in the language-led variants. Because behaviour and personality changes can be some of the hardest parts for families to process emotionally, since it can feel like losing someone while they're still physically present, specialist FTD support (through Dementia UK's Admiral Nurses, or a local young-onset dementia service) is often more directly useful than generic dementia support built around memory loss.
A word from The Care Compass
If a diagnosis has never quite matched what you're actually living with, the personality that seems to have quietly changed, the words that used to be there and now aren't, that gap is real, and FTD is common enough that it deserves to be asked about directly, not stumbled across on a forum after months of not being taken seriously.
This article is for general guidance only and does not constitute medical advice. If you're worried about sudden or severe changes, contact 111 for urgent but non-emergency concerns, or 999 in an emergency.
Common Questions
What is the difference between frontotemporal dementia and Alzheimer's?
In frontotemporal dementia, changes in personality, behaviour or language usually appear first, often with memory staying relatively intact in the early stages. In Alzheimer's, memory loss is typically the first and most obvious sign. FTD also tends to start younger — it's the most common cause of dementia diagnosed before 65.
What is semantic dementia?
Semantic dementia is one of three language-led variants of frontotemporal dementia, grouped under the term primary progressive aphasia. It causes a gradual loss of the meaning of words and concepts — someone might still speak fluently but increasingly not understand what familiar words, objects or even faces actually mean.
Is frontotemporal dementia genetic?
It can be. Around a third of cases run in families, most often linked to changes in one of three genes (C9orf72, GRN or MAPT). The majority of cases, though, happen without any known family history.
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