The three studies described in this Doctoral Thesis pertain to the neurotransmitter serotonin, the environmental factor light, and their role in the regulation of human mood as well as behavioural and perceptual aspects of daily social interaction. Participants were healthy at the time of the study but considered at risk for mood disorders in the future. In Study 1, the serotonin system was manipulated by administering tryptophan. This resulted in a decrease in quarrelsome behaviours, an increase in agreeable behaviours, and improved mood. Changes in perceptions of others were also seen. In Study 2, acute tryptophan depletion was used in conjunction with dim or bright light exposure during test days. A worsening of mood was seen under dim but not bright light conditions, which suggests that bright light was able to regulate mood by interacting with the brain serotonin system. In Study 3, this idea was explored further by investigating the links between light exposure levels and mood, as well as social behaviours and social perceptions, in everyday life. Higher levels of natural bright light exposure were associated with less quarrelsomeness, more agreeableness, and better mood. In conclusion, serotonin appears to mediate aspects of human social interaction that have been linked to a variety of mental and physical health issues. Bright light may regulate mood in part by altering the activity of the brain serotonin system. An increase in bright light exposure may have effects on mood and social interaction similar to a pharmacological manipulation of the brain serotonin system. The findings of the three studies presented here may have implications for the development of a nonpharmacological approach to the prevention of mental as well as physical disease. The various processes underlying factors that modulate social inclusion and acceptance deserve more attention in psychiatry and human neuroscience.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.111846 |
| Date | January 2006 |
| Creators | Aan het Rot, Marije. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Division of Neuroscience.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002599039, proquestno: AAINR32288, Theses scanned by UMI/ProQuest. |
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