The news for sufferers of Seasonal Affected Disorder is that the cause seems to by physical one.
Scientists at the University of Copenhagen have been carrying out tests on subjects to try and find out if there is a physical trigger for SAD – experienced by one in six people in more northerly climates, where the winter is worse.
Differences in the way our bodies deal with seratonin can now explain why some are affected more than others.
If you experience symptoms of lacking energy, wanting to sleep a lot, overeating or feeling depressed, you may be suffering from SAD.
To see the full article, go to Brain scans releval why up to one in six poeple get sad in winter
http://www.spring.org.uk/2014/10/brain-scans-reveal-why-up-to-one-in-six-people-get-sad-in-winter.php