Depression and dementia are often thought of as entirely separate conditions; however, growing research suggests that the relationship between the two is more complex. Current evidence indicates experiencing depression, particularly in midlife, may increase a person’s risk of developing dementia in future.
The Lancet 2024 report reviewed current evidence on risk factors for dementia. It documented depression as a potentially modifiable midlife risk factor. Current understanding of the mechanisms linking depression to dementia are unknown.
Current hypotheses include linking potential behavioural and lifestyle change side effects of depression, such as withdrawing socially, exercising less, having poor sleep patterns and engaging in less mentally stimulating activities, as the possible cause of increased risk of future cognitive decline.
The Lancet also hypothesises another theory of how depression may increase dementia through causing an over secretion of cortisol. This is thought to potentially lead to hippocampal atrophy or an inflammatory response which may develop into cognitive decline.
A key piece of evidence that the Lancet also reported was findings from a UK Biobank study, which stated that people who were treated for depression either by medication, or talking therapies, or both were less likely to develop dementia than the untreated group. However, this was an observational study, so maybe open to the bias of observational studies.
Further research is clearly needed within this area, but this information does highlight important considerations. Early identification of depression in midlife is likely important, because depression may potentially be a modifiable risk factor for developing dementia in later life. Seeking timely and appropriate support for not only a diagnosis of depression but also by engaging in treatment may reduce the risk of developing dementia.
Therapies such as counselling, medication, lifestyle changes, and social support can significantly improve symptoms. The encouraging news is that depression is often treatable and treating it may help protect brain health.
There is also increasing evidence that maintaining overall mental wellbeing—such as through physical activity, social engagement, and cognitive stimulation—can help build resilience against depression.
In summary understanding there is a link between depression and dementia highlights the importance of viewing mental and cognitive health as deeply interconnected. Looking after your mood is not just about feeling better in the present, it may also be an investment in your future brain health.
If you or someone you know is experiencing persistent low mood, memory concerns, or changes in behaviour, seeking professional advice is an important first step. Early support can make a meaningful difference, both emotionally and cognitively.
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