Research from Aarhus University in Denmark has revealed a significant connection between depression and the later development of Parkinson’s disease and Lewy body dementia. Symptoms of depression often appear several years prior to the formal diagnosis of these neurological conditions, suggesting that mental health could serve as an early warning sign.
The study, led by clinician-scientist Christopher Rhode and his team, analyzed health records from more than 17,000 individuals diagnosed with either Parkinson’s disease or Lewy body dementia between 2007 and 2019. The researchers compared these patients with control groups suffering from chronic illnesses such as rheumatoid arthritis, chronic kidney disease, and osteoporosis, totaling over 108,000 subjects.
Findings Highlight Timely Clinical Awareness
The results indicated that individuals with Parkinson’s disease or Lewy body dementia had a notably higher risk of experiencing depression compared to those with other chronic conditions. Alarmingly, the incidence of depression began to increase approximately eight years before the formal diagnosis of either neurological disorder, remaining elevated for at least five years post-diagnosis.
“Following a diagnosis of Parkinson’s disease or Lewy body dementia, the persistent higher incidence of depression highlights the need for heightened clinical awareness and systematic screening for depressive symptoms in these patients,” the authors noted in their published paper in General Psychiatry.
This research builds on previous studies linking depression to both conditions but offers a clearer timeline and a more controlled comparison by including patients with other serious illnesses. The association was found to be particularly strong in those ultimately diagnosed with Lewy body dementia, which may be related to how this disease impacts brain chemistry linked to mood and its tendency to progress more aggressively than Parkinson’s disease.
Implications for Future Screening and Treatment
The median age at which participants received a diagnosis of either condition was 75. The researchers propose that individuals diagnosed with late-life depression should be screened for early signs of neurodegeneration. By including patients with other chronic illnesses, the team aimed to eliminate confounding factors that may influence depression rates, suggesting that it is not solely a consequence of living with serious health conditions.
“Our findings align with those from prior studies, the majority of which have also observed increased prevalence and incidence of depression both prior to and following the diagnosis of Parkinson’s disease and Lewy body dementia,” the researchers stated. They emphasized that their approach, which included patients with other chronic conditions, could help control for disabilities associated with Parkinson’s and Lewy body dementia.
While the study shows a strong association, it stops short of proving causation. Other factors, such as sleep disturbances, may contribute to both conditions, warranting further research to explore these connections.
Parkinson’s disease affects over a million people in the United States, impacting mood, memory, and motor functions due to the degeneration of dopamine-producing neurons. Similarly, Lewy body dementia, characterized by protein clumps in the brain, also affects cognitive abilities and movement in a significant number of individuals.
Given the absence of cures for these conditions, using depression as an early indicator may facilitate earlier intervention. Identifying neurological issues sooner could enable better support, improved treatment options, and further opportunities to study the diseases’ root causes before they become more advanced.
“Given the established associations between depression, cognitive decline, and accelerated disease progression, early detection and treatment of depression in this patient population may be crucial,” the researchers concluded. They advocate for integrating mental health assessments into routine neurological care to enable timely antidepressant therapy or other interventions. The implications of this research could transform how clinicians approach the mental health of patients at risk for these debilitating neurological conditions.
