Adults in Aotearoa New Zealand who have ever been diagnosed with a mental health disorder face a significantly increased risk of developing dementia later in life, according to new research. The findings highlight an urgent need for investment in our struggling mental health sector.
In the latest Briefing from the Public Health Communication Centre, Dr Etuini Ma’u and co-authors from the Department of Psychological Medicine at the University of Auckland report that common mental health conditions such as depression and anxiety substantially increase a person’s risk of developing dementia later in life.
Using data from the New Zealand Health Survey, the researchers followed adults who had reported a diagnosis of depression, anxiety, or bipolar disorder to assess their future risk of dementia:
- Anxiety was linked to a 30% higher risk of dementia
- Depression increased the risk by 40%
- Bipolar disorder was associated with nearly a threefold increase
- Psychological distress more than doubled dementia risk; severe distress nearly tripled it
- People who rated their health as “poor” had three times the dementia risk of those who rated it “excellent”
“Mental health and wellbeing are shaped by childhood experiences, and life stressors are amplified by poverty and social disadvantage. A life-course approach to mental health is essential,” says Dr Ma’u. “That means supporting children, whānau and communities, not just treating illness when it reaches crisis point.”
Between 2016 and 2023, the number of New Zealanders reporting moderate to severe anxiety or depression symptoms rose by more than 50%. A similar increase was seen in psychological distress. Alarmingly, the number of people reporting they couldn’t get the mental health support they needed also rose by 50%.
“We urgently need coordinated, long-term action,” says Dr Ma’u. “Mental health is a foundation for brain health. Ignoring it now means paying a much higher price later.”
Dementia rates in Aotearoa NZ are projected to double within 25 years, soaring from an estimated 83,000 cases today to 167,000 by 2050.