To print: Select File and then Print from your browser's menu --------------------------------------------------------------------------------------- Title: PET Scans Help Identify Mechanism Underlying Seasonal Mood Changes URL: http://www.pslgroup.com/dg/22A756.htm Doctor's Guide September 2, 2008
CHICAGO -- September 2, 2008 -- Brain scans taken at different times of year suggest that the actions of the serotonin transporter vary by season, according to a study in the September issue of Archives of General Psychiatry. These fluctuations may potentially explain seasonal affective disorder and related mood changes. Nicole Praschak-Rieder, MD, and Matthaeus Willeit, MD, Centre for Addiction and Mental Health and the University of Toronto, Ontario, and colleagues studied 88 healthy individuals (mean age 33) between 1999 and 2003. Participants underwent one positron emission tomography (PET) scan to assess serotonin transporter binding potential value, an index of serotonin transporter density. For the analysis, individual scans were grouped according to the season of the scan -- fall and winter or spring and summer. "Serotonin transporter binding potential values were significantly higher in all investigated brain regions in individuals investigated in the fall and winter compared with those investigated in the spring and summer," the authors wrote. When they matched binding potential values to meteorological data, the researchers found that higher values occurred during times when there were fewer hours of sunlight per day. "An implication of greater serotonin transporter binding in winter is that this may facilitate extracellular serotonin loss during winter, leading to lower mood. Higher regional serotonin transporter binding potential values in fall and winter may explain hyposerotonergic symptoms, such as lack of energy, fatigue, overeating, and increased duration of sleep during the dark season." "These findings have important implications for understanding seasonal mood change in healthy individuals, vulnerability to seasonal affective disorder, and the relationship of light exposure to mood," the authors concluded. "This offers a possible explanation for the regular reoccurrence of depressive episodes in fall and winter in some vulnerable individuals." SOURCE: Archives of General Psychiatry --------------------------------------------------------------------------------------------- Copyright © 1999 P\S\L Consulting Group Inc. All rights reserved. Republication or redistribution of P\S\L content is expressly prohibited without the prior written consent of P\S\L. P\S\L shall not be liable for any errors, omissions or delays in this content or any other content on its sites, newsletters or other publications, nor for any decisions or actions taken in reliance on such content. --------------------------------------------------------------------------------------------- This news story was printed from *Doctor's Guide to the Internet* located at http://www.docguide.com --------------------------------------------------------------------------------------- Return to News Story Page This site is maintained by webmaster@pslgroup.com Please contact us with any comments, problems or bugs. All contents Copyright (c) 1998 P\S\L Consulting Group Inc. All rights reserved.