This meta-analysis looked at seventeen studies involving adults with mild cognitive impairment to see if depression affects the risk of developing Alzheimer's disease or all-cause dementia. The researchers examined data from these studies to understand the connection between mental health and cognitive decline.
The results showed an association between depression and an increased risk of progression to Alzheimer's disease overall. When the data was adjusted for other factors, the link remained significant for all-cause dementia, though the link to Alzheimer's specifically was not statistically significant after adjustment. The overall risk of progression was higher in people with depression compared to those without.
However, the certainty of this evidence is very low because the studies varied greatly in how they measured depression and outcomes. This high variation makes it hard to draw firm conclusions about the exact size or consistency of the risk. Readers should understand that this is a link, not proof that depression causes dementia progression.