From Light to Language: Using Linguistic Features and Language-Use to Predict Circadian-Related Disorders

This thesis investigates whether the ancient association between darkness and depression may be due to the physiological effect of darkness (and light) on our mood. It examines how blue-enriched light affects negative self-thoughts, and whether people with severe depression spontaneously use darkness language to describe their experiences. The research found that blue-enriched light reduces negative self-thoughts, making it easier to reject negative self-thoughts. Additionally, individuals with extremely severe depression were more than twice as likely to describe their experiences using darkness metaphors. These findings suggest that darkness metaphors reflect actual changes in how people with depression perceive and think about themselves.