Young Onset Dementia – Not the Same as Late Onset Dementia

By Anita Goh, Clinical Neuropsychologist and Director of Social Gerontology at the National Ageing Research Institute (NARI); Kevyn Morris, Dementia and Disability advocate, NARI Community Advisory Panel member, living experience of dementia; Gwenda Darling, Dementia and aged care activist, 2025 NSW Senior Australian of the Year Nominee, NARI Community Advisory Panel member, living experience of dementia.

When people think of dementia, they often imagine someone who is older. However, dementia does not only affect people over the age of 65. The rising prevalence of dementia around the world also includes an increase in people living with young-onset dementia (YOD), sometimes referred to as early-onset dementia.

YOD affects people who are often still working, driving, raising families, caring for older relatives and actively engaged in their communities, making its impact particularly complex and far-reaching.

However, YOD is not simply “dementia that happens earlier”. It is a different experience entirely, from symptom onset to diagnosis, treatment, and care.  A 2025 study found the global number of YOD diagnoses more than doubled from 1990 to 2021.

Yet despite its prevalence, awareness and support remain limited.

Why does diagnosis take so long?

YOD remains more challenging to diagnose and manage due to its very varied presentation. This means that early symptoms often don’t look like memory loss. Instead, people might first experience changes in mood, personality, language or executive function, and these also change over time.

Individuals under 65 years old rarely fit the image of someone living with dementia, leading many professionals (including GPs, psychiatrists and neurologists) to potentially overlook dementia when presented with thinking or behaviour changes in younger people.

Diagnostic tools are also often designed for older populations and not validated for people under 65. As such, too often symptoms of dementia are misdiagnosed as mental health issues or substance use. Symptoms like confusion, mood changes, or withdrawal can resemble mental health issues such as depression, anxiety or psychosis.

Accurate and early diagnosis can make all the difference, allowing for better post-diagnostic care that is timely, personalised, and age-sensitive to significantly improve quality of life and help individuals and families navigate the journey with confidence.

To learn more about YOD and diagnosis, you can subscribe to the Australian Journal of Dementia Care.