A new study has found that depression in older adults may be an early indicator of developing Parkinson’s disease or Lewy body dementia, sometimes appearing years before motor or cognitive symptoms manifest. Researchers at Aarhus University in Denmark analyzed national health records to investigate the connection between these neurodegenerative diseases and depression, comparing patients diagnosed with Parkinson’s or dementia to those with chronic conditions like rheumatoid arthritis, chronic kidney disease, and osteoporosis.
The study, published in the journal General Psychiatry, examined data from 17,711 individuals diagnosed with Parkinson’s or dementia between 2007 and 2019. Findings revealed a significantly higher risk of depression among individuals who later developed Parkinson’s disease or Lewy body dementia compared to those with other chronic illnesses. Notably, depression rates began to increase approximately eight years before an official diagnosis of either neurological condition, and remained elevated for at least five years post-diagnosis.
“We found compelling evidence that depression signals the development of Parkinson’s disease or Lewy body dementia later in life,” said Christopher Rohde, the clinical scientist who led the research team. The findings, reported by Beirut Time, corroborate earlier research linking depression to both Lewy body dementia and Parkinson’s disease, both before and after diagnosis (Rohde et al., Gen. Psychiatry, 2025).
The research builds on growing evidence suggesting that changes in the brain associated with these neurodegenerative diseases can begin long before noticeable physical symptoms appear. A report from Al Arabiya highlighted that the study suggests depression may not always be a transient psychological disorder in older adults, but rather a sign of underlying brain changes.
The Gulf News reported that the Aarhus University study indicated depression serves as an early warning sign for serious brain diseases like Parkinson’s or Lewy body dementia, preceding the onset of characteristic motor or cognitive symptoms. The study did not find the same elevated rates of depression among individuals with other chronic conditions, suggesting a unique relationship between depression and these specific neurodegenerative diseases.
