Got the Seasonal Blues?
by Ashley
Many of us look forward to the time of the year when the clocks are pushed back and the seasons start changing. However, for many people this can be a very difficult time. For years, mental health professionals have questioned whether or not seasonal mood swings are caused by a chemical imbalance of Serotonin. Serotonin is a chemical messenger that transmits nerve signals. It moderates one’s mood (sadness, anger, aggression, etc…) and physiological functions (mating, eating, sleeping, etc…). Low serotonin levels have been linked to depression and mood-swings. The level of Serotonin in the brain is determined by the amount of sunlight you are exposed to. When the clocks are pushed back during the fall and winter months, it gets darker earlier, which results in less sunlight exposure. When less light is received by the human body, the serotonin levels decrease, resulting in depression.
A study conducted by Nicole Praschak-Rieder, M.D., and Mathaeus Willeit, M.D. of the the Centre for Addiction and Mental Health and the University of Toronto involved taking 88 healthy people around the age of 33, and doing PET (positron emission tomography) scans to detect the amount of Serotonin in the brain. These tests were done between December 1, 1999 and December 9, 2003. The test results of the serotonin levels were then related to meteorological data. These tests also show the amount of activity of the Serotonin transporters. Serotonin transporters help regulate the mood-altering neurotransmitter of Serotonin in the brain. The higher the transporter activity, the lower the Serotonin level is. This study showed that brain scans taken at different times of the year varied.
In the fall and winter months they found a higher transport activity in the individuals tested at that time, than the individuals tested during the spring and summer months. The potential value of the serotonin transporters in the fall and winter months compared to the spring and summer months were .01 to .001. “The binding potential values showed negative correlations with average duration of daily sunshine in all brain regions. (p= -.021 to -0.39, P= .05 to <.001)." Since the values of the transporter activity were higher, the Serotonin circulated less in the brain. Since we are exposed to the sun less during the fall and winter months, the Serotonin levels are less. This study has shown that low Serotonin levels in the brain during the colder months with less sunlight exposure, may result in the seasonal blues.
So, fall and winter months=less sunlight= high transporter activity= lower serotonin levels.
Do you think this study is accurate? Would gender play an important part in determining the results of the tests done? Would other health conditions affect the results? What about the environment and temperature? Do you feel the effects of low serotonin levels in the winter months?
November 2nd, 2008 at 4:43 pm
This seems very interesting. I would not have guessed that the time of year would effect how you feel. I noticed that the study did not mention the location of the people during the four years. If the study was high in latitude, then this would mean that the winter would have a great effect on the persons serotonin levels. If the study was closer to the equator than winter would not have as much of an effect. Would there be a possiblility of the altitude/ longitude being related to the amount of serotonin levels?
November 3rd, 2008 at 4:02 pm
I enjoyed reading this post. I think this is accurate although I don’t really understand how high transporter activity relates to low serotonin levels. It seems to me that Christmas is in the wrong season if people are going to be depressed due to low levels of Seratonin. Or maybe Christmas is in the perfect month becasue people’s depression will lead them to find happiness in anyway they can, so they spend more money in the winter months and at Christmas. In contrast to this article http://www.psychologytoday.com finds that there are more suicides in the spring and summer than fall in winter, at least in a 10 year study they have performed in an Australian city, so maybe serotonin does not have the depression effect after all. I think it is funny how sunlight controls an important part of our bodies. We sound like plants in this article. This article also proves once again that sun is the source of energy and life for our biosphere and that without it there would be no life and we would be crazy depressed people with mood swings all of the time. I also believe that the lack of serotonin in the winter due to lack of sunlight will affect people who have pessimistic attitudes much more than someone who is optimistic and happy. I think it depends on what type of person you are and what your attitude is.
November 5th, 2008 at 12:18 am
Wow, Ashley, great post! I thought being a little down and depressed on cloudy, cold winter days was all in my head…well, turns out it actually is! This seems like a very accurate study, especially since it uses PET scans, which have recently been implemented to test serotonin levels in the brain because they use the most advanced technology available. I read a little more about differences in serotonin levels between genders, and research I found at http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=24674 shows that the rate of the synthesis of serotonin is 52% higher in males than females. This is very interesting, considering that statistics from the Mayo Clinic (http://www.mayoclinic.com/health/depression/MH00035) show that twice as many females than males suffer from chronic depression. This seems to directly correlate with serotonin level. In light of this, I think that the results of the seasonal study should be observed separately in males and females. If both genders were tested together, the natural difference in production of serotonin must be taken into account before the results could be analyzed according to season. Other health conditions, mainly neurological disorders, such as depression or anxiety, also effect serotonin levels, therefore affecting possible results of the study. Just some food for thought: Since the amount of sunlight affects serotonin levels, which then affects mental state, would depression be more or less common in places close to the equator? Further away?