Mood Disorders After 40 May Signal Dementia Risk: Study

Mood disorders like depression, mania, or bipolar disorder after age 40 may be early indicators of neurodegenerative diseases, not just mental health issues, a new study suggests.

Researchers from Japan’s National Institutes for Quantum Science and Technology (QST) found a strong link between late-life mood disorders and early signs of dementia-related brain changes.

The study, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, focused on 52 participants with late-life mood disorders (LLMDs) and 47 healthy individuals.

Advanced brain imaging revealed that about 50 per cent of LLMD participants had abnormal tau protein buildup, a key feature of several brain diseases. In contrast, only 15 per cent of healthy controls showed such signs.

Using PET scans with two tracers, researchers detected both tau and amyloid beta proteins, both associated with Alzheimer’s.

Nearly 29 per cent of LLMD patients also had amyloid deposits, compared to just 2 per cent of healthy individuals.

Autopsy results from 208 cases further supported these findings.

Individuals with LLMDs had significantly higher instances of tau-related brain diseases. These abnormal proteins were particularly present in the frontal regions of the brain, responsible for emotion and cognition.

Neurodegeneration can start with psychiatric symptoms

Lead author Dr Shin Kurose noted that most LLMD participants had mild or no cognitive symptoms, strengthening the idea that neurodegenerative diseases can begin as psychiatric disorders.

On average, mood symptoms appeared 7.3 years before any motor or cognitive signs of diseases like Alzheimer’s.

The findings suggest that early detection of late-life mood disorders could help identify individuals at risk of dementia well before memory loss sets in.

The researchers advocate for timely diagnosis and early intervention with disease-modifying treatments to delay or reduce the impact of neurodegenerative conditions.

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