Psychological distress is significantly linked to the development of dementia later in life, new research shows.
Results from a population-based study of nearly 70,000 participants showed that symptoms of psychological distress, defined as experiencing stress or having a depressive mood, exhaustion, and nervousness during the past month, were associated with a 20% increased risk for dementia.
Dr Sonja Sulkava
Distress can increase levels of stress hormones and neuroinflammation, lead investigator Sonja Sulkava, MD, PhD, a researcher at the National Institute for Health and Welfare at the University of Helsinki, Finland, told Medscape Medical News.
“Animal studies have clearly shown that chronic stress increases the neuropathology of memory disorders” via tau-mediated pathology, as occurs, for example, in Alzheimer’s disease, she said.
Sulkava also noted that psychological distress can be closely related to insomnia, which can also increase risk for memory disorders.
“Psychological distress may also lead to other unhealthy lifestyle behaviors or avoidance of medical screening, which increases the dementia risk,” she added.
The findings were published online December 15 in JAMA Network Open.
Long Follow-up
The investigators analyzed information from the National FINRISK Study, a Finnish health and risk factor study in which data from random samples of Finnish inhabitants residing in different areas of the country were collected every 5 years between 1972 and 2007.
Participants answered questions about their levels of stress, depressive mood, nervousness, and exhaustion over the past month. Follow-up continued until death, diagnosis of dementia, or end of year 2017. This information came from the Finnish Hospital Discharge register, the Causes of Death Register, and the Drug Reimbursement Register.
Among nearly 68,000 participants, about 8000 received a diagnosis of dementia over a mean follow-up of 25 years. However, many participants (19,600) died before they could be assessed for dementia, the investigators note. The mean age at the time of death without dementia was 71 years; the mean age at onset of dementia was 79 years.
Investigators found that overall, reporting exhaustion “often, during the past month,” increased risk of later dementia by 17%; reporting nervousness “often, during the past month,” increased the risk by 21%; reporting depressive mood “often, during the past month,” increased the risk by 22%; and reporting stress “more than other people, during the past month,” increased the risk by 24%.
Sulkava said that she would like to see how symptoms of psychological distress evolve with age, as they only had cross-sectional data on different ages in their study.
In the current analysis, there was an association between symptoms that were reported at an early age (<45 years) and dementia later in life.
“It is possible that those individuals also experience symptoms between the ages of 45 and 65,” Sulkava noted. She added that they would like to know more about how the risk develops as people age.
Enduring Patterns
In an accompanying editorial, Yoram Barak, MD, associate professor of psychiatry at the University of Otago in Dunedin, New Zealand, agreed.
“These findings suggest that to solve the conundrum surrounding the association of depression and anxiety with risk of dementia, we need to look into the enduring patterns of perceiving the internal and external environment over long periods and through phases of the lifecycle,” Barak writes.
He also notes that it is “the biopsychosocial reaction to and management of stress that are likely associated with risk of developing dementia.”
While the FINRISK samples are population-based, nonparticipation of some prevents direct generalizability to the Finnish population or to other populations, the investigators note.
“Our results on internal associations of the study sample are, however, in line with the previous studies on psychological symptoms” and dementia risk, Sulkava said.
The study was funded by the Emil Aaltonen Foundation, the Maud Kuilstila Memorial Foundation, the Academy of Finland, and the Gyllenberg Foundation. Sulkava has received grants from the Emil Aaltonen Foundation and from the Maud Kuilstila Memorial Foundation. The other investigators and Barak have reported no relevant financial relationships.
JAMA Netw Open. Published online December 15, 2022. Full article, Editorial
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