The association between darkness and depression is well established. Now a March 25 study in the Proceedings of the National Academy of Sciences reveals for the first time the profound changes that light deprivation causes in the brain.
Neuroscientists at the University of Pennsylvania kept rats in the dark for six weeks. The animals not only exhibited depressive behavior but also suffered damage in brain regions known to be underactive in humans during depression. The researchers observed neurons that produce norepinephrine, dopamine and serotonin—common neurotransmitters involved in emotion, pleasure and cognition—in the process of dying. This neuronal death, which was accompanied in some areas by compromised synaptic connections, may be the mechanism underlying the darkness-related blues of seasonal affective disorder.
Principal investigator Gary Aston-Jones, now at the Medical University of South Carolina, speculates that the dark-induced effects stem from a disruption of the body’s clock. “When the circadian system is not receiving normal light, that in turn might lead to changes in brain systems that regulate mood,” he says.
Treating the rats with an antidepressant significantly ameliorated brain damage and depressive behaviors. “Our study provides a new animal system for antidepressant development. Many existing animal models depend on stress. Our model is a stress-free means of producing a depression. It might be particularly relevant to seasonal affective disorder, but we think that it is relevant to depression overall,” Aston-Jones says.
Editor's Note: This story was originally printed with the title "Down in the Dark"
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20 Comments
Add CommentDoes this mean people who live in the northern regions of North America could expirence a small form of brain damage, when they expirence long periods of darkness throughout the year? I wonder what happens when there is large amounts of light are given to people. Could the outcome be reversed, or is the drastic change too much for the brain, could it help or disrupt the neurotransmitters. Do full spectram lamps actuall help aleviate the problem or just medicate it. Some neuroimaging should be done on people who live up north. Take subjects who have lived there for only a couple of years and some who have been living in it for generations.
Reply | Report Abuse | Link to thisThat makes a lot of sense. Its it possible though that since the amount of light has an effect on neuronal death in certain areas of the brain that too much light may also effect others? I mean look at people in Florida, not exactly a state of Einsteins.
Reply | Report Abuse | Link to thisIf the problem is a disruption of circadian rhythm, can it be partly ameliorated by setting an alarm clock for the same time every morning? I find that after I do that for about a week I will consistently wake up a few minutes before the alarm goes off. Have any studies been done on using other rhythm sources to replace light?
Reply | Report Abuse | Link to thisAs a resident of Northern Canada I can safely say that 'living in the dark' is a challenge. During the winter months when light is low or none existent most people find that keeping social circles open or just keeping busy keeps 'Cabin Fever' away. It is true that Depression happens but only to very few people. I have lived in the North for many years and find that the Summer months with NO darkness more difficult than to much Darkness. You body refuses to slowdown for sleep when the sun is blazing overhead at 2AM. That is more of a concern than the Dark.
Reply | Report Abuse | Link to this"Does this mean people who live in the northern regions of North America could expirence a small form of brain damage, when they expirence long periods of darkness throughout the year?"
Reply | Report Abuse | Link to this---
No, as they live in houses with lights, go to stores with lights, etc.--and even the times when the sun does not rise (in areas above the Arctic Circle), there are still small amounts of light outside from the sun near the horizon for a few hours a day, which then often reflects off of the snow.
YsTD
Reply | Report Abuse | Link to thisAll light is not created equal. Wavelength components of artifical light fall in a very narrow band. Onthe other hand, using light therapy that approxiimates that of natural sunlight has been disappointing to the point of being pretty useless.
Reply | Report Abuse | Link to thisIs it reasonable to apply findings of a study where rats are completely deprived of light for 6 weeks to the biology of humans who are getting a little less light than they are accustomed to. It is a very weak analogy. If they had deprived the rats of food for 6 weeks would you apply the findings to humans on a diet?
light is the most fantastic physics of the universe
Reply | Report Abuse | Link to thisjust imagine, if light never arrived here from space, our species might not have altered our behavior enough to build telescopes and send probes to Mars
light obviously has an impact on behavior more far-reaching than mere depression
light is the most amazing physics in the universe
Reply | Report Abuse | Link to thisjust imagine, if light never arrived here from space, our behavior might not have been changed enough to build telescopes or send probes to Mars
obviously light has a fundamental effect on behavior, the experiment on depression validates the point
Another useless experiment tormenting rats to develop yet another drug to help people that maybe, just maybe, are exeriencing seasonal effective disorder because they're now indoors with the windows closed breathing their own carbon dioxide, their skin has closed up to maintain heat resulting in increased toxic load, eating foods such as starches and meats that are plentiful and warm during winter months and eating less fruit, and getting little skin exposure to the sun resulting in loss of circulating Vitamin D.
Reply | Report Abuse | Link to thisI don't know any people who are kept in the dark for six weeks. Why don't they just study rats that live in Seattle?
Another useless experiment tormenting rats aimed at development of yet another pharmaceutical. Maybe, just maybe seasonal affective disorder is caused by:
How many people do you know suffering from seasonal affective disorders have been kept in a dark room for six months? Why don't these so-called scientists study rats living in Seattle. Reply | Report Abuse | Link to this
Whoops. Didn't mean to post twice.
Reply | Report Abuse | Link to thisThis makes a lot of sense to me. I worked a night shift full-time for about two and a half years. I finally switched to a day shift a couple of months ago, and my mood and outlook on life in general is much better. While I'm sure the absence of light was a significant factor, there's also the simple fact that my social network was much smaller because no one else I knew was living on my schedule. Even though I no longer work the night shift on a regular basis, this past week I had to cover for the person who took it over from me, and the entire week I felt like complete hell.
Reply | Report Abuse | Link to this'Depressed feelings' often may come in times and places in which there is unending strong light. The monotonous nature of the unending sunny clime has driven many people away from it. And there are those who find too strong light interrupts their own creative efforts.
Reply | Report Abuse | Link to thisIs it possible then that it is the face of excess more than anything else- excess of Light and perhaps most especially excess of Darkness- which leads to negative Mood and Feeling?
Recently there's other article that says something like: "when the eye receive enought light, it release a kind of chemical that promote brain's 'plasticity'".
Reply | Report Abuse | Link to thisMaybe they're related to this news.
JOANNE, post twice, post three times, because it was a very good, insightful comment. I live in a fairly large flat/apartment, and not much air from outside gets in, even with all the windows open. However, I've noticed on very windy days, my mood really picks up, I feel a lot different, more positive, I have more energy, I feel more alive, and it dawned on me that, perhaps, lack of oxygen is affecting my health - among other factors. I use full spectrum bulbs because I live in gloomy old England.
Reply | Report Abuse | Link to thisJOANNE, post twice, post three times, because it was a very good, insightful comment. I live in a fairly large flat/apartment, and not much air from outside gets in, even with all the windows open. However, I've noticed on very windy days, my mood really picks up, I feel a lot different, more positive, I have more energy, I feel more alive, and it dawned on me that, perhaps, lack of oxygen is affecting my health - among other factors. I use full spectrum bulbs because I live in gloomy old England. I'm now thinking of buying some small oxygen containers with masks attached, so I can get a few bursts of oxygen when I'm feeling lousy :)
Reply | Report Abuse | Link to thisThe winter "blahs" to me definitely relate to the lack of light.
Reply | Report Abuse | Link to thisLeaving to work before sunrise, and returning home after dark is really a drag.
I really don't mind the cold, and actually love the snow.
Springtime to me means a welcome return to LIGHT!
I live in Mexico City and had depression that worsened in dark days. I used light therapy combined with excercise and an active social life. It worked much better than Prozac!
Reply | Report Abuse | Link to thisNow I use light therapy on winter (that is nothing really in Mexico) but it is still useful.
I don?t know if I could live in Canada!
There has been a great deal of study on lighting and the circadium rhythm and the release of hormones into the body's system. These are not just beneficial, but also can cause the body many issues regarding health. I work in a maternity/baby unit at my local hospital. The managers who are on the normal rhythum( work day, sleep nights) have come up with the idea that we night shift workers must have the lights turned off, since everyone is , of course sleeping at night. Why can't educated managers???? realize this is our day, and many will have depression, anxity and physical issues relating to turning our lights our. This is our day shift.
Reply | Report Abuse | Link to thisWe sleep during the day, not at night.