It is estimated that more than 55 million people worldwide suffer from dementia, and this number is expected to increase sharply over the next 25 years – up to 153 million. Currently, there are no drugs for this disease. In their study, scientists aimed to identify modifiable risk factors that can be observed in middle age to delay or even prevent the onset of this neurodegenerative disease, according to “Newsweek”.
In 2024, the Lancet commission identified depression as a “potentially modifiable midlife risk factor” that increases the likelihood of developing dementia. The research team sought to investigate this link between midlife depression and dementia later in life in more detail. First, scientists analyzed public health data on 5,811 UK residents (aged 35–55 at the start of the study); this data was collected in two phases: 1985–1988 and 1997–1999.
Individuals who exhibited five or more symptoms of depression during initial screenings were classified as having depression. Later, the research team monitored the patients’ health records up to 2023 to determine how many participants later developed dementia and what forms it took.
Over the two-decade observation period, 10.1% of the initial study participants developed some form of dementia. The researchers identified six symptoms associated with midlife depression that, according to them, indicate an increased risk of dementia. These are:
- Loss of self-confidence.
- Feeling unable to cope with problems.
- Lack of warmth and tenderness towards others.
- Constant nervousness and tension.
- Dissatisfaction with how tasks are performed.
- Difficulty concentrating.
“Our study results show that the risk of dementia is associated with certain symptoms of depression, rather than depression as a whole,” said study author, UCL health psychologist Philipp Frank, in a statement. “This allows us to understand much more clearly who may be at greater risk, decades before dementia develops. Everyday symptoms experienced by many people in midlife seem to provide important information about long-term brain health. Paying attention to these signs could open up new opportunities for early prevention.”
The researchers noted that their analyzed data did not include known dementia risk factors such as the APOE4 gene, cardiometabolic conditions, and lifestyle factors. According to the research team, for individuals under 60 at the start of the study, the six mentioned symptoms “fully” explained the link between midlife depression and dementia risk.
The study results also showed that participants diagnosed with depression in midlife later faced a 27% higher risk of developing dementia. However, it was found that this increased risk was entirely due to the six depression symptoms observed in adults younger than 60.
Particularly important is that loss of self-confidence and difficulty solving problems were associated with about a 50% higher risk of dementia. Although this is the first large-scale long-term study examining whether specific depression symptoms drive the link between midlife depression and later-life dementia, the majority (71.7%) of study participants were men.
This leaves an opportunity for researchers in future studies to better investigate the impact of midlife depression on women’s brain health.
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