A research study out of UC San Francisco indicates that poor mental health in early adulthood can lead to poor cognition down the road. In this study, they followed approximately 15,000 participants between the ages of 20 and 89. What they found was that if someone suffered from depression in early adulthood, that may lead to a decline in cognition in later life. According to Willa Brenowitz, PhD, MPH, of the UCSF Department of Psychiatry and Behavioral Sciences and the Weil Institute for Neurosciences, “Several mechanisms explain how depression might increase dementia risk. Among them is that hyperactivity of the central stress response system increases production of the stress hormones glucocorticoids, leading to damage of the hippocampus, the part of the brain essential for forming, organizing and storing new memories.” [1]
[1] https://www.sciencedaily.com/releases/2021/09/210928121341.htm