Skip to comments.Depressed Hamsters Shed Light on Seasonal Disorder
Posted on 01/10/2006 1:44:43 PM PST by billorites
As the days grow shorter and cold, and darkness settles in, some begin to feel a little blue -- hamsters and people alike.
Up to 20 percent of Americans report they feel more depressed during the winter months as a result of a condition known as seasonal affective disorder. Now scientists have shown that hamsters experience the same sluggishness when their exposure to light is reduced. By studying these sad hamsters, the researchers hope to find new ways of helping people combat seasonal depression.
"Hamsters aren't perfect models, but the mechanisms may be similar -- as in what's going on in the brain that causes seasons to change emotional behavior," explained Leah Pyter, a graduate student in neuroscience at Ohio State University in Columbus.
How do you know when a hamster is depressed? Pyter explained there were a few tests established in laboratory science that claimed to determine the mood of the rodents.
For example, if the animals spend more time hovering near the walls of their containers, rather than at the center, it's believed they feel more anxious. If they decline to slurp up tempting offers of sugar water, scientists take it as a sign of depression. Another test involves placing the animals in water and seeing if they swim or simply give up and float. Hamsters don't sink apparently, but float in water.
"The sooner they give up in the water, the more depressed they are," Pyter said. "If you give them an antidepressant they don't give up as quickly."
In her research, led by OSU's Randy Nelson, 53 female and 48 male Siberian hamsters were housed in containers simulating either long summer days (16 hours of light) or short winter days (eight hours of light). After about 60 days in their fluorescent-lit environments the hamsters were tested to measure their level of anxiety and depression. Pyter and Nelson found a clear link between the amount of light exposure and the hamsters' state of minds.
"Our results do suggest a relationship between season and symptoms of depression and anxiety," Nelson said.
The researchers then went further and tested whether the animals' exposure to light in the days after their birth had an impact later in life. Studies in people have suggested that those born during the winter months may be more vulnerable to depression. Sure enough, Pyter and Nelson found that baby hamsters born to short artificial days were more likely to show signs of depression and anxiety later in life.
"Animals born in short days still had some depressive behaviors even when they were exposed to longer days as adults," Pyter said. Nonetheless, she added that the amount of light the animals were exposed to as adults seemed to have more influence on mood than the amount of light they were exposed to as baby hamsters.
For those of us in the Northern Hemisphere, the shortest day of the year is fast approaching. Dec. 21 is winter solstice when the sun shines directly over the Tropic of Cancer and then sinks from the sky sooner than all other days of the year. How does the sun's path affect our mood? Norman Rosenthal, author of "Winter Blues: Everything You Need to Know About Seasonal Affective Disorder," says it may be linked to a time when humans had no access to artificial light.
"It's natural to enter a hibernationlike state as the days get shorter," he said. He explained that the hormone melatonin was secreted during the night and played a role in people and animals as they regulated their daytime mood and energy level.
"Artificial light has helped us keep our melatonin levels steady," he said. "What is happening is people perceive the artificial light as sunlight. Patients with seasonal affective disorder may be undersensitive to light, so they do not perceive the artificial light as an extension of the day."
Rosenthal is hopeful that studies, like those with the hamsters at OSU, may help yield more effective drugs for those most affected by SAD. But, for those whose depression is mild enough to avoid the use of drugs, he recommends other ways of combating the seasonal blues.
Some studies have shown that flicking on extra bright fluorescent light boxes at dawn or as soon as you wake can help diminish the effects of seasonal affective disorder.
Wake up early
Fighting the urge to "hibernate" through the morning hours can help you feel better throughout the day.
Rosenthal suggests that going for a walk or jog, or doing some other form of exercise can also help beat the blues. Exercising is even more effective against SAD if done outside during bright daytime hours.
It may be the time of year that you crave comfort foods that are full of starches and sugar, but Rosenthal says these foods can exacerbate seasonal affective disorder.
Spend as much time outside as possible and when inside, try to maximize your exposure to natural sunlight.
If all else fails and if you have the time and money, take a vacation to a sunny place.
It could be worse.
The hamsters could've belonged to Richard Gere.
Now THOSE are some depressed animals!
They'd perk up if only Richard Gere would return their phone calls.
Beat me by 42 seconds!
Even hamsters get the blues.
I wonder if there have been any studies on the opposite effect? I feel 100% better when the weather is dark, dreary and cold. Too much sunlight depresses me. I think I reach my light quota for the year in 3 days.
So of course I'm in the deep south where there IS no winter and summer is 10 months long.
Explains why I've been in a very bad mood for most of my life-lol!
I have a friend in Australia who works in a mental health clinic, and I am told that their admission rates skyrocket during this time of the year, and down under it's summer!
I have S.A.D. and I would be happy if they would come out with some medication to make me hiberate for real every winter.
These tests conducted on poor, helpless creatures are an outrage. The perps should be sentenced to involuntary confinement in dark basement. Let's see how depressed the "scientists" get then!
My hamsters only got depressed whin I wouldn't let them roam around the house in their little plastic ball.
"I feel 100% better when the weather is dark, dreary and cold."
Those hamsters are the leadership of the Demagogic Party - no wonder they're all so depressed, they are pathetic whining rodents and they know it!!!
"So of course I'm in the deep south where there IS no winter and summer is 10 months long.
Explains why I've been in a very bad mood for most of my life-lol!"
You may have a talent for psychological research.
There is a factual error.
The sun does not sink from the sky earlier on Dec 21st than any other day.
The earliest sunset in the northern hemisphere is on about Dec seventh. From then on, it sets a bit later each day.
The problem is that it still RISES later each day, until about Jan 5th or so.
The net results are that Dec 21 is the shortest day of the year.
I feeled more cheery just reading this reporter's name on her by-line.
I had a similar experience in Boston when I used to wrestle. I would go to school when it was dark, have a three hour wrestling practice and run 6 miles after practice. As a result I did not see any sun for extended periods of time.
As a result I woke up at EXACTLY 4:17 every morning. Like groundhog day I would open my eyes, no matter how tired and find that I had woken up at 4:17. My sister read that the sun resets your inner clock. I made a point to wear lots of layers and run outside or just make time to see the sun. Problem went away.
Take that back. My daughter had a hamster that had more personality than most of the liberals I know. His favorite activities included chasing the cat with his hamster ball and hanging out on the hamster pad next to my keyboard while my daughter got him his evening snack.
Sounds like my mother, her house is like a coffin, all dark and closed up.
I gotta have tons of sun to survive. If we have more than one dreary rainy day I'm starting to hit bottom. But come summer I 'm a happy camper!
All people should take extra Vitamin D during the winter. And most folks could use a bit extra during the summer months as well.
Recent studies on Vit D have shown it to be almost miraculous.
Another test involves placing the animals in water and seeing if they swim or simply give up and float. Hamsters don't sink apparently, but float in water. "The sooner they give up in the water, the more depressed they are," Pyter said. "If you give them an antidepressant they don't give up as quickly."
Some folks have all the fun.
Don't you mean gerbils?
Here in Minnesota, we just had 13 consecutive days with a total of 2 1/2 hours of direct sunlight.
At least there's the warm glow of the computer moniter (viewing FR, of course).
Wish someone would tell my dwarf hamsters they are supposed to be depressed. The last few weeks they are all more active and want much more attention than they usually do.
Is that where they come out and see their shadows there will be 12 more weeks of whimpering.
I think I love you.
Except for the bars...
Ah- but here is where I do not follow pattern yet again!
My house is not dark and dreary. Its all white and bright colors and reflective surfaces. I don't even like wood furniture, just chrome and glass.
I just like OUTSIDE being dreary and cold. Little birdies frozen in the trees, no sun for months and months. My grandmother was from the high Pyrenees and loved dark,bitter days tool; so I come by it naturally.
I think I could live happily in the Arctic if only there were a humongous mall!
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