1st February 2024

Young Onset Dementia

When someone develops dementia before the age of 65, it is called young onset dementia. It causes cognitive and behavioural problems apart from neuropsychiatric symptoms. There is an increase in cases in the UK. It affects not only the individual but their entire family as well.

It is also called ‘early onset’ or ‘working age’ dementia. However, this is subjective and is becoming less pertinent as services are focused on not just the individual but also the impact. 

Unfortunately, individuals with early onset dementia postpone meeting the professionals for assessment and delay a diagnostic assessment. On the other hand, there are reports that patients and their families sometimes must move ‘from pillar to post’ before gaining access to appropriate services. The longer time to reach diagnosis can have a knock-on effect on family stress, work sickness and loss of earnings, delays in treatment, increased cognitive problems and functional decline, depression or anxiety and missed opportunities to participate in research.

Evaluation and management include detailed clinical assessment and bio-psycho-social management as per individual dementias mentioned above.

Epidemiology

• It is seen in individuals between 45-65 years.
• It is estimated that 42,325 people in the UK have been diagnosed with young-onset dementia. (Ref Dementia UK, 2nd edition 2014, Alzheimer’s Society).  
• They represent around 5% of the 850,000 people with dementia. 
• The actual figure could be higher because of the difficulties of diagnosing the condition and may be closer to 6-9% of all people with dementia. 
• Awareness in primary care is still comparatively low, and when individuals are still functioning or working, symptoms are often recognised as stress, depression or anxiety rather than dementia.
• Young onset dementia is not only uncommon but is challenging to distinguish. Since they are younger, they find it difficult to admit anything wrong, especially when they are healthy, resulting in delayed presentation with the doctors.
• People with young-onset dementia are more likely to have a hereditary form of dementia. 
• Young-onset dementia seems to be higher among BAME groups.  
• Likewise, another group of individuals with a higher prevalence is those with Intellectual disabilities. Studies have shown that 1 in 10 people with a learning disability develop young-onset Alzheimer’s disease between the ages of 50 to 65. 
• The number of people with Down’s syndrome who develop Alzheimer’s disease is even greater, with 1 in 50 developing the condition aged 30-39, 1 in 10 aged 40-49, and 1 in 3 people with Down’s syndrome will have Alzheimer’s in their 50s and almost 1 in 2 at 60 years.

Pathophysiology

• Presenile Alzheimer’s dementia can run in families and is autosomal dominant. It can be due to mutations of presenilin 1 or 2 genes. 
• Likewise, frontotemporal lobar degeneration can occur in individuals between ages 45 and 65 usually and could be due to genetic causes, especially involving a mutation of tau genes.
• Huntington’s dementia can be caused due to expansion of the CAG repeat sequence. It is inherited as an autosomal dominant condition. 
• Vascular dementia due to physical morbidities can also be responsible. 
• Cerebral vasculitis is one of the treatable causes

Common types/causes of Young onset dementia (This list is not exhaustive):

1. Young-onset- Alzheimer’s dementia
2. Young-onset- Vascular dementia
3. Young-onset- Frontotemporal dementia
4. Korsakoff’s syndrome
5. Young-onset- Lewy body dementia
6. Parkinson’s dementia
7. Huntington’s dementia
8. Creutzfeldt-Jacob dementia

References

• www.alzheimers.org.uk. (2021). Young-onset dementia | Alzheimer’s Society. [online] Available at: https://www.alzheimers.org.uk/about-dementia/types-dementia/young-onset-dementia
• Sampson, E.L. (2004). Young-onset dementia. Postgraduate Medical Journal, 80(941), pp.125–139. doi:https://doi.org/10.1136/pgmj.2003.011171.
• Young Dementia Network. (n.d.). Resources for clinicians. [online] Available at: https://www.youngdementianetwork.org/resources/resources-for-clinicians/ [Accessed 21 Feb. 2023].
•  www.rcpsych.ac.uk. (n.d.). Young-onset dementia in mental health services (CR217 Oct 2018). [online] Available at: https://www.rcpsych.ac.uk/improving-care/campaigning-for-better-mental-health-policy/college-reports/2018-college-reports/cr217 [Accessed 21 Feb. 2023]
• Jefferies, K. and Agrawal, N. (2020). Young-Onset Dementias. [online] Cambridge University Press. Available at: https://www.cambridge.org/core/books/abs/clinical-topics-in-old-age-psychiatry/youngonset-dementias/E45582319E62BC20D6756D760B34309D [Accessed 21 Feb. 2023].