A paper in the journal Neurology reports on a correlation between cynical distrust in old age and dementia. From the abstract:
“Higher cynical distrust in late life was associated with higher mortality, but this association was explained by socioeconomic position, lifestyle, and health status. Association between cynical distrust and incident dementia became evident when confounders were considered. This novel finding suggests that both psychosocial and lifestyle-related risk factors may be modifiable targets for interventions. We acknowledge the need for larger replication studies.”
As always, note that this is correlational research and does not prove causation.