Late-Life Mood Disorders Could Signal Early Alzheimer's Insights
Revised Article:
Mood disorders that first manifest later in life (LLMDs) could be early signs of neurodegenerative diseases, according to a new study.
These conditions, such as depression and bipolar disorder, observed in individuals over the age of 40, may indicate an ongoing neurodegenerative process rather than simply psychiatric issues.
Keisuke Takahata, MD, PhD, the chief researcher at the National Institutes for Quantum Science and Technology in Japan, explained that previous postmortem brain studies suggest a link between LLMDs and dementia, but the specific underlying mechanisms are unclear.
"We've long known that depression and dementia that occur in old age share common pathologies. However, what we haven't known is the pathophysiological relationship between them," Takahata told Medical News Today.
For the study, published in the Journal of Neuroscience, researchers recruited 52 participants with LLMDs over the age of 40 and 47 age-matched healthy controls. Using positron emission tomography (PET) scans and analyzing brain tissue from autopsy cases, they found:
- About 50% of participants with LLMDs had tau accumulation and 29% had amyloid deposits, compared to only 15% and 2%, respectively, in the control group.
- The abnormal protein amounts could be detected years before traditional cognitive symptoms appeared, with mood symptoms preceding cognitive or motor symptoms by an average of 7.3 years in autopsy cases.
"These findings solidify the emerging paradigm that diagnoses of Alzheimer's disease (AD) and non-AD tauopathies are increasingly informed by objective molecular markers," Takahata said. "It also encourages the use of PET biomarkers to identify at-risk individuals at a much earlier stage — perhaps even before meeting the criteria for mild cognitive impairment."
Richard A. Bermudes, MD, a board-certified psychiatrist, commented that these findings validate what's been observed clinically and that treating late-life depression isn't just about managing mood symptoms.
"This isn't just about treating mood symptoms anymore — we're potentially intervening in the earliest stages of neurodegeneration," Bermudes explained. "The finding that 50% of late-life mood disorder patients showed tau pathology compared to only 15% of healthy controls means we've been underestimating the stakes."
Early detection could transform the entire approach to neurodegenerative diseases, according to Bermudes, who emphasizes the importance of aggressive, multimodal intervention for late-life depression.
Similar sentiments were shared by Gary Small, MD, chair of psychiatry at Hackensack University Medical Center, highlighting that this study is consistent with previous research concerning the link between amyloid and tau accumulation in the brain and mood disorders.
"Numerous studies indicate that early detection and intervention are crucial for neurodegenerative diseases," Small said. "It is easier to protect a healthy brain than to attempt to repair neural damage once it becomes extensive."
Future studies using amyloid and tau PET, along with other neurodegenerative biomarkers, will shed light on early detection and prevention strategies, he added.
- Neurological disorders like Alzheimer's disease might be preceded by mood disorders that manifest later in life, as suggested by a recent study in the Journal of Neuroscience.
- The study found that approximately half of participants with late-life mood disorders had tau accumulation, a factor commonly associated with Alzheimer's disease and other neurological disorders.
- Depression in older individuals could be an early sign of a neurodegenerative process, which might eventually progress into health-and-wellness issues like Alzheimer's disease or other mental-health conditions.
- With early detection of these abnormal protein accumulations in the brain, scientists can potentialy identify at-risk individuals before the onset of cognitive impairment, allowing for earliest stages of neurodegeneration to be addressed, according to Richard A. Bermudes, a board-certified psychiatrist.
- The link between amyloid and tau accumulation in the brain and mood disorders has been observed in various studies, and experts like Gary Small, MD, suggest that future research focusing on early detection using amyloid and tau PET scans can lead to effective strategies for prevention and intervention of Alzheimer's disease and other neurological disorders.
