When it comes to mental health, every generation has a story – and understanding those stories side by side can change the future.
That’s the driving force behind the Sax Institute’s new 18 and Up Study, a landmark project that will follow Australians aged 18 and up, to understand the influences on mental health and well-being. Together with our long-running 45 and Up Study, which has already shaped major health policy and practice across the country, this new study will provide one of the world’s most powerful intergenerational resources on mental health and wellbeing.
Filling a missing piece of the puzzle
We already know that mental health challenges are rising, especially among younger Australians. The latest national data shows almost 40% of people aged 16–24 experienced a mental disorder in the past year – the highest figure ever recorded. Rates among people in their 30s and 40s are also significant, with around 1 in 5 Australians aged 25–44 reporting a disorder in the same period.
Despite these numbers, there’s been surprisingly little long-term research following people through early and mid-adulthood. Most existing studies focus either on adolescents or on older Australians. The 18 and Up Study fills that crucial gap, providing a clearer picture of what life looks like in the decades when careers are built, families are formed, and financial pressures often peak and will help us better understand how life events, access to care and support, and wider changes in society impact mental health.
Looking across generations
One of the most powerful aspects of the 18 and Up Study is that it doesn’t stand alone. It is designed to connect with our long-running 45 and Up Study, which has already followed more than 250,000 Australians aged 45 and older for almost two decades.
This means the 18 and Up Study will evolve into a truly multigenerational initiative, with children and even grandchildren of 45 and Up participants being invited to take part. For the first time, we will be able to see how mental health and wellbeing play out across three generations of Australian families.
What we’re aiming to answer
Mental health is not just an individual story – it is shaped by families, communities and the broader systems we live in. By capturing experiences across generations, the study will help answer big questions such as:
- How are challenges and risks carried across family lines?
- What strengths and protective factors can be passed down?
- How can policy break harmful cycles and build resilience for future generations?
- When and why are mental health problems most likely to emerge or persist in adulthood?
- How do economic and social pressures – from housing affordability to work insecurity – affect mental health?
- What protective factors help people in their 20s, 30s, and 40s maintain good mental health, and how can policy strengthen these supports?
- How do patterns observed in younger Australians connect with those tracked in the 45 and Up Study, and what does this reveal about intergenerational risks and strengths?
Building a healthier future
The study will follow hundreds of thousands of Australians over time, linking survey responses with health and social data. This will give policymakers, service providers and communities the reliable evidence they need to design better supports – not just for one generation, but for all of us.
As Sax Institute CEO and Chief Investigator of the 18 and Up Study Dr Martin McNamara explains:
“The 18 and Up Study is about making sure we understand the realities of adult life in Australia today – the challenges and the opportunities – and learning how those experiences shape mental health over time. Together with the 45 and Up Study, this work will help create a healthier, more resilient future across generations.”
PUBLICATION DATE
29 September 2025
