One last thought about depression…

In this transitional weather period we are experiencing so early here in Maine, I have been thinking about seasonal affective disorder (SAD), which is a subtype of depression or bipolar disorder.  For me, my favorite seasons are summer and spring because I love having the sunshine.  It feels as though I can function better when it is warm and sunny out (ironic that I go to school in Maine!).  But, I feel that this happens to many people, some experience it to a greater degree than others.  So I researched SAD a bit and found that it is a DSM categorized disorder, but its specific causes are unknown.  Factors that have been found to play a role in this disorder are your biological circadian clock, melatonin levels and serotonin levels.  Symptoms include depression, anxiety, loss of energy, social withdrawal, oversleeping.  Treatments include light therapy, anti-depressants, or CBT.  This disorder can sometimes lead to major depression.

This interests me because it brings me back to the crossroads between brain and behavior.   Researchers don’t know the specific cause of SAD, thus there is a link missing in this brain pathway.  Are external factors (i.e. lack of sunlight) affecting behavior, which in turn affects the brain chemicals and thus can lead to major depression? Or is there a predisposed chemical imbalance that makes some more vulnerable to this disorder than others?   According to Webmd.com, people who live in areas where there are shorter days are at a greater risk of developing this disorder, suggesting that behavior changes brain.   On the other hand, according to this same website, people who have relatives who have had SAD are at a greater risk as well, suggesting that chemical imbalances in the brain affect this behavior.  Another interesting point: according to Forbes magazine, a study conducted using the Gallop World Poll to look at citizen satisfaction in 140 countries, found that Denmark was “the happiest place on Earth”.   Most of the peoples’ satisfaction is based on overall good health.  This is an interesting statistic because Denmark is cold and has very short days.  The average number of days that it rains per year is 170!  That’s almost every other day!  It seems as though more people would be likely to suffer from SAD in Denmark because of these statistics!

On another note, it is interesting that one of the treatments for SAD is anti-depressants.  This brings me back to our discussion about coping or preventing these disorders.  It seems that anti-depressants are not the appropriate treatment for this type of disorder, especially because the specific cause is unknown.  Like Solomon mentioned, whenever we don’t feel “normal” we try to treat it using medication.  For people experiencing SAD, they may feel as though anti-depressants are the only treatment, but more research must be done to determine whether this is appropriate before just handing out this powerful drug like candy.   A better option may be light therapy or CBT, where people can learn to cope with these seasonal depression bouts without going straight to medication.  In this case, a reoccurring saying may be appropriate. Mind over matter.

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9 thoughts on “One last thought about depression…

  1. Great Post Sara! I read this paper a couple of years ago about SAD. The researchers found that mutations in melanopsin (a pigment in the eye ganglion cells controls circadian rhythms by sending information directly to the SCN) may contribute to the etiology of SAD. Mutations in this pathway may alter serotonin and melatonin levels because the SCN innervates the pineal gland and stimulates the release of melatonin! Serotonin is released somewhere in the pathway. Interestingly, I thought the best form of treatment was a special lamp that gives off more light! Silly me!! 🙂

    On the other hand, it does not surprise me that doctors administer anti-depressants because Scientists still cannot decide if the problem comes from insufficient serotonin or melatonin. It is possible that something crazy is going on with both of them since they are apart of the tryptophan biological pathway. There is this “new” antidepressant called agomelatine–it is a melatonin receptor agonist and a serotonin receptor antagonist. I wonder if it can be used to treat SAD in addition to the light lamp?

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  2. Interesting paper, Sharonda! I think light therapy is still used as well so that would make sense in accordance with your findings! That is also interesting about agomelatine. From your findings, it would make perfect sense that it would be a melatonin receptor agonist and serotonin receptor antagonist. Maybe this is more effective than light therapy (which I have a hard time believing would be that effective!!) Thanks for all that great info 🙂

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  3. This seems to me another great case of the environment and genetics interacting. I wonder what the biological differences are between those who experience SAD and those who don’t.

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  4. Very cool post, Sara! And interesting follow-up, Sharonda!

    I had previously been under the impression that it was pretty clear that the sunlight was clearly a direct factor in SAD, thus it is very interesting that there is potentially a genetic factor. I would love to know more about this aspect. Perhaps it is as simple as people with relatives who have had SAD are for the most part in a similar environment or more aware of the disorder. I would be curious to know more about this potential genetic factor in SAD.

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  5. Wow, the thought of treating something like that with anti-depressants scares me a little. One must maintain a steady regiment of anti-depressants for up to months before they begin to work. They are not intended to be off and on again drugs; by the time the medication evens begins to work, Summer may have already arrived. One could also say that they work more directly for seasonal depression than for general depression, reaping benefits from the serotonin reuptake inhitibing properties of the meds rather than on the long term collateral effects other systems. In that case, however, these collateral changes may make for some rather unintended side effects. On a related note, the weather here has been very nice lately, and I am beginning to feel happier every day!

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  6. Lisa! I found a recent paper on melanopsin mutations and SAD. Here is the reference:

    Roecklein KA, Rohan KJ, Duncan WC, Rollag MD, Rosenthal NE, Lipsky RH, Provencio I. (2009). A missense variant (P10L) of the melanopsin (OPN4) gene in Seasonal Affective Disorder. Journal of Affective Disorder, 114, 279-285.

    I cannot find the article I read in 2008. Oh well. Hope that helps!

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  7. I was also thinking the familial component could be due to living in similar/nearby regions- it would be interesting to look into that further with families whose members were very spread out in different regions. Do you think SAD becomes less common the closer to the equator a country is located? Although the study on Denmark kind of throws a wrench in that idea, perhaps length of day has more to do with it than intensity of light?

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  8. Maybe a melanopsin mutation only means that a person has a higher chance of getting SAD when there is limited exposure to light. I think your idea is interesting Hannah. Can someone develop a similar disorder in situations where light intensity never really changes? Can too much light alter the same neurohormones, especially if their rhythmic release is regulated by external light?

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  9. Sara this is a really interesting topic. I too wonder about SAD in relation to exposer to sun/day length. I was also thinking about if you spend your childhood in a sunny place and move to a less sunny place if this could some how effect the occurrence of SAD. In other words is there an optimal time where sunlight has an effect on development and changes in the brain?

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