Lack of Sunlight Linked to Depression
Sunlight is often labeled as something to avoid as it is blamed for causing skin cancer. While it is true that overexposure to sunlight can be a contributor to melanoma, a lack of sunlight is associated with reduced cognitive function among depressed people.
Science Daily recently published a release examining the writings of researchers in BioMed Central’s Environmental Health. During this study, researchers gathered weather data from NASA satellites to measure sunlight exposure throughout the United States. This information was linked to the prevalence of cognitive impairment in depressed people.
The team of researchers was led by Shia Kent from the University of Alabama at Birmingham. “We found that among participants with depression, low exposure to sunlight was associated with a significantly higher predicted probability of cognitive impairment. This relationship remained significant after adjustment for season,” said Kent.
“This new finding that weather may not only affect mood, but also cognition, has significant implications for the treatment of depression, particularly seasonal affective disorder.”
This study generated speculation that the physiological mechanisms that are associated with seasonal depression may also have something to do with sunlight’s effect on cognitive function in the context of depressive symptoms. This function was evaluated by measuring the short-term recall and temporal orientation.
While sunlight helps to regulate the hormones serotonin and melatonin, it has also been shown to affect brain blood flow. This has in turn been linked with cognitive functions.
According to Kent and researchers, “Discovering the environment’s impact on cognitive functioning within the context of seasonal disorders may lead not only to better understanding of the disorders, but also to the development of targeted interventions to enhance everyday functioning and quality of life.”