Using a variety of tests, researchers found more symptoms of depression and anxiety in adult hamsters that were housed for weeks in conditions with limited daylight, as they would find in winter, when compared to hamsters who had days with longer daylight.

The research also examined whether hamsters that developed prenatally and then were born during short days were more likely to suffer from depression and anxiety as adults. The results for these tests were mixed, but suggest that hamsters born in winter-like light conditions had increased depressive symptoms as adults.

Overall, the results suggest that the season the hamsters were born in, their sex, and the changing of the seasons all may play a role in levels of depression and anxiety.

"These results in hamsters may provide some insight into the development of seasonal affective disorders in humans," said Randy Nelson, co-author of the study and professor of psychology and neuroscience at Ohio State University .

"Our results do suggest a relationship between season and symptoms of depression and anxiety

Nelson conducted the study with Leah Pyter, a doctoral student in neuroscience at Ohio State . They presented their results Nov. 15 in Washington , D.C. at the annual meeting of the Society for Neuroscience.

The study involved 53 female and 48 male Siberian hamsters. They were offspring of breeding pairs housed in either long days (16 hours of light a day, such as found in summer) or short days (8 hours of light per day, such as found in winter). Following birth, the hamsters remained in the same light period until weaning (about 20 to 23 days of age). After weaning, about half were transferred into the opposite light period in other words, some who were in short days went to long days, and vic
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Contact: Randy Nelson
Rnelson@osu.edu
614-538-9526
Ohio State University
15-Nov-2005