Darkness Linked To 'Brain Drain' In Depressed People

http://www.sciencedaily.com/releases/2009/07/090727191728.htm

ScienceDaily (July 29, 2009) — A lack of sunlight is associated with reduced cognitive function among depressed people. Researchers writing in BioMed Central's open access journal Environmental Health used weather data from NASA satellites to measure sunlight exposure across the United States and linked this information to the prevalence of cognitive impairment in depressed people.
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Kent and his colleagues speculate that the physiological mechanisms that give rise to seasonal depression may also be involved in sunlight's effect on cognitive function in the context of depressive symptoms. Cognitive function was assessed by measurement of short-term recall and temporal orientation. As well as regulating the hormones serotonin and melatonin, light has been shown to also affect brain blood flow, which has in turn been linked with cognitive functions.