Researchers at Aarhus University Hospital in Denmark have found that depression in older adults may be an early indicator of Parkinson’s disease and Lewy body dementia. The results of the study were published in General Psychiatry.

The authors analyzed medical data from more than 17,700 elderly Danes who were later diagnosed with Parkinson’s disease or Lewy body dementia. They found that symptoms of depression in these individuals appeared long before the official diagnosis and gradually increased, peaking approximately three years prior to disease detection.

A comparison with older patients suffering from other chronic conditions—including rheumatoid arthritis, kidney disease, and osteoporosis—showed that the increased risk of depression could not be explained solely as a psychological reaction to declining health. No similar rise in depression risk was observed with these other chronic illnesses.

According to the researchers, 30–40% of patients with Parkinson’s disease or Lewy body dementia experience depression, with a higher incidence in the latter group.

The authors emphasize that depression alone does not mean that a neurodegenerative disease will inevitably develop. However, in older adults, it can serve as an important warning sign of increased risk and a reason for closer medical monitoring and early screening.

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