Depressive and insomnia symptoms together linked to dementia risk
Both symptoms were linked to higher dementia risk than neither, with a hazard ratio of 1.37, a relative measure of risk.
Our read
Populations- Studied:
- Cohort study of 6,226 community-dwelling older adults without dementia, up to 12 years
- What changed:
- Dementia risk was higher with co-occurring depressive and insomnia symptoms than with neither symptom (hazard ratio 1.37)
- The catch:
- Depressive symptoms can be early signs of dementia rather than a cause
Editor of record: Boris Djordjevic · AgingResearch.News
US adults living in the community—6,226 people aged 65 and older without dementia at entry—took part in an observational cohort study with up to 12 years of follow-up. Participants reported depressive symptoms and difficulty falling asleep or returning to sleep. Researchers updated symptom groups at each interview and identified dementia using reported diagnoses, cognitive tests and an informant questionnaire.
Both symptoms together were associated with higher dementia risk than neither symptom or insomnia symptoms alone. Risk did not clearly differ from depressive symptoms alone. During follow-up, 2,377 participants developed dementia. Differences between groups were more apparent before age 75. At 75 and older, depressive symptoms alone were linked to higher dementia risk than both symptoms together.
Why it matters
For assessing dementia risk in later life, the authors supported considering mood and sleep symptoms together. They suggested depressive symptoms may be more informative than insomnia symptoms, with differences by age.
Caveats
Symptoms were self-reported, and dementia classifications included possible cases based on cognitive tests. Early dementia changes may have contributed to mood or sleep symptoms; the findings concern community-dwelling adults aged 65 and older.
From the paper
- Participants
After applying these criteria, the analytic sample consisted of 6226 community-dwelling older adults (Round 1 n = 3956, Round 5 n = 2270) without dementia at baseline who were followed for up to 12 years to ascertain incident dementia and death.
- Follow-up
After applying these criteria, the analytic sample consisted of 6226 community-dwelling older adults (Round 1 n = 3956, Round 5 n = 2270) without dementia at baseline who were followed for up to 12 years to ascertain incident dementia and death.
- Result
Adjusting for sociodemographic and health factors, participants reporting neither symptom had a significantly lower hazard of dementia than those in the co-occurring group (HR = 0.73, 95% CI: 0.65–0.81, q < 0.001).
Results, Time-varying depressive-insomnia symptom groups and incident dementia
- Limitation
Although we conducted a 2-year and 5-year lag sensitivity analyses excluding early dementia cases, longer prodromal periods cannot be ruled out, and causal interpretation should be made with caution.
Quoted word for word from the full text on PubMed Central.
The paper
Depressive and insomnia symptoms and incident dementia risk: A 12-year study in U.S. older adults
Johns Hopkins University
Journal of Affective Disorders, May 16, 2026, Open access, accepted manuscript
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