Dementia that develops before 65 years of age
Young-onset dementia (YOD) is defined purely by age of onset, before age 65, rather than by a distinct disease process. It is not a separate disease, but a term used to describe any type of dementia occurring at a younger age.
Any of the recognised types of dementia can occur at a younger age, including:
- Alzheimer’s disease
- frontotemporal dementia
- vascular dementia
- primary progressive aphasia
- Lewy body dementia
- less commonly, other neurodegenerative or inherited conditions.
While Alzheimer’s disease remains the most common cause of dementia, even when patients are less than 65 years of age at onset, frontotemporal dementia and primary progressive aphasia occur disproportionately more often in YOD.
YOD often presents differently to how people expect dementia to look. Early symptoms may involve changes in personality, behaviour, or language rather than memory loss, particularly when the underlying cause is frontotemporal dementia or primary progressive aphasia. Because of this, and because dementia is not usually expected in younger people, symptoms are often initially attributed to stress, burnout, depression, relationship difficulties or menopause, which can delay diagnosis.
Practical impacts of YOD
Young-onset dementia carries practical impacts that differ from those typically associated with older-onset dementia, including:
- access to age-appropriate services and supports, since many existing dementia services are designed with older adults in mind
- continuing employment and career responsibilities
- financial commitments, such as mortgages or supporting dependent children
- parenting or caring responsibilities for children or teenagers
- relationship and identity changes at a life stage not usually associated with cognitive decline.
What happens in the brain?
The brain changes in young-onset dementia are the same as those seen in the underlying disease type and are not unique to younger age. For example:
- Alzheimer’s disease at a younger age still involves amyloid and tau protein changes
- frontotemporal dementia at a younger age still involves tau or TDP-43 protein changes
- vascular dementia at a younger age still involves brain injury from reduced blood flow.
What differs at younger ages is not the biology itself, but:
- which underlying diseases are more likely to be responsible
- how symptoms may be interpreted or delayed in diagnosis.
What increases the risk of young onset dementia?
Risk factors for young onset dementia depend heavily on the underlying cause, but some general patterns are recognised.
Factors that can’t be changed include:
- family history – having a close relative with young onset dementia increases the likelihood of an inherited cause, and genetic counselling may be recommended in these situations
- genetics – a higher proportion of young onset dementia cases are linked to specific inherited genetic changes compared with dementia that develops later in life, particularly for certain forms of Alzheimer’s disease and frontotemporal dementia
- underlying neurological or genetic conditions – some rarer inherited conditions can cause dementia-like symptoms earlier in life.
Which risk factors may be modifiable?
Factors that may be modifiable, meaning they could potentially be addressed through lifestyle or medical care, include:
- alcohol use – heavy, long-term alcohol use is associated with a form of cognitive decline that can present as young-onset dementia
- cardiovascular health – high blood pressure, diabetes, high cholesterol and smoking can contribute to vascular-related young-onset dementia, similar to their role in vascular dementia at any age
- head injury – a history of significant head injury has been linked to increased dementia risk generally, including at younger ages.
Because young-onset dementia is more likely than late-onset dementia to have an identifiable genetic or reversible cause, thorough specialist assessment is particularly important, both to guide treatment and to determine whether other family members may be at risk.
Common patient questions
Yes, dementia can occur in younger adults, although it is more common with increasing age.
Dementia is not usually expected in younger people, so symptoms are often first attributed to stress, mental health conditions or life circumstances. Symptoms can also differ from the memory-focused presentation many people associate with dementia, particularly when personality, behaviour or language changes come first.
Support needs often differ from those of older adults with dementia, particularly around employment, finances and parenting responsibilities. Speaking with your GP or specialist about referral to age-appropriate health and government support services is an important early step.