The JAMA Neurology study found that both sleeping six hours or less and sleeping nine hours or more per night were associated with more depressive symptoms and more napping compared to sleeping seven or eight hours per night.
Notes on verification
Directly confirmed by PubMed abstract and JAMA Neurology publication (Winer et al., 2021), corroborated by independent secondary summary from Alzheimer Europe.
Sources
- How much sleep keeps cognitive decline at bay? - Harvard Health (health.harvard.edu)
- https://pubmed.ncbi.nlm.nih.gov/34459862/ (pubmed.ncbi.nlm.nih.gov)
- https://www.alzheimer-europe.org/news/new-research-jama-neurology-explores-impact-sleep-duration-amyloid-accumulation-and-cognitive?language_content_entity=en (alzheimer-europe.org)
- https://jamanetwork.com/journals/jama/article-abstract/2785733 (jamanetwork.com)