Well, its almost that time of year again. Morning walks to Sparks are slowly becoming morning bus rides as the weather is getting increasingly colder. Your bed and Netflix seem slightly more inviting than going out and dealing with the wind and bipolar temperatures. Before we know it, the trees will shed all of their fall leaves and winter weather will kick in. For some people, especially college students, something else comes along with the cold weather. This is seasonal depression, or Seasonal Affective Disorder (SAD), which is defined as “a depression that occurs each year at the same time, usually starting in fall, worsening in winter, and ending in spring.” (“Seasonal Depression”) It’s no surprise that some people generally do not enjoy the winter months, but is it really possible that this discomfort can actually have a biological affect on the body?
Studies done at the National Institute of Mental Health in 2001 seem to support this hypothesis. Based on research done of a span of about 75 years, scientists have attributed this depression to the changes in light and darkness that occur during the different seasons. Seasonal depression had since been linked to a hormone called melatonin, which controls a person’s “circadian (day/night) bio-rhythm.” In simpler terms, this cycle of wake and sleep is connected to the eye’s ability to sense light and darkness so during the “melatonin secretion” cycle, melatonin is decreased as morning approaches, reminding us to wake up.
The experiment conducted by the Institute of Mental Health included 55 patients diagnosed with SAD and 55 healthy patients, all stationed in a dimly lit lab. Each patient’s melatonin secretion cycle was measured every 30 minutes throughout a 24 hour period once per season. The results showed that the patients with SAD had a secretion cycle that was 38 minutes longer in the winter than during the summer. Contrary, the control group showed little differences in the melatonin cycle. Although the sample size was small in this experiment, the results act as strong evidence towards the idea that patients with SAD may experience elongated melatonin cycles. What this does not prove, is that melatonin is the cause of seasonal depression or that these changes are particularly damaging to one’s health.
Further research led me to the practice of phototherapy or light therapy, which is often used to treat patients diagnosed with SAD. Studies done on that subject have concluded that the level of light and the time of exposure are both essential for treating this disorder. Experiments showed that light under1500 lux has no effect on a person’s “respiration, blood pressure, body temperature, body temperature, the internal clock, and the regulation of production of [melatonin]” (“Seasonal Affective Disorder”). After drawing this conclusion, the researchers decided they needed to expose patients to levels higher than 1500, which better represents outdoor lighting. This did cause change in all of those factors (although I saw no data to show how drastic), but proved only to have a positive effect when patients were exposed to the light in the morning.
To put into simpler terms how these experiments relate directly to seasonal depression, the shortened hours that the sun is out during the day in the winter supposedly causes biological changes that scientists claim cause depression. My issue with this theory is that most people who are diagnosed with this disorder tend to stay in the house as much as possible and as studies have shown, indoor lighting has no affect on melatonin levels or any other bodily function.
When I first became aware of seasonal depression, I was in denial that it could be a legitimate condition. Although the little experimentation I could find on the subject claimed that seasonal depression was a result of several biological changes, I do not believe there is enough evidence to support that hypothesis. However, I do see a strong link between light changes and melatonin levels. In my opinion, I would not be legitimately concerned if the shift to cold weather has you feeling the “winter blues.”
Sources
- “Seasonal Depression.” Cleveland Clinic. The Cleveland Clinic Foundation, n.d. Web. 21 Oct. 2014. <http://my.clevelandclinic.org/services/neurological_institute/center-for-behavorial-health/disease-conditions/hic-seasonal-depression>.
- “Seasonal Affective Disorder (SAD).” Lighting Design Lab. Lighting Design Lab, n.d. Web. 21 Oct. 2014. <https://www.lightingdesignlab.com/seasonal-affective-disorder-sad>.
- Xue, Xin. “Seasonal Affective Disorder Strikes in Wintertime.” Iowa State Daily. Iowa State Daily, Ames, Iowa, 30 Nov. 2011. Web. 21 Oct. 2014. <http://www.iowastatedaily.com/news/article_2175af2e-1bba-11e1-9cf3-001cc4c03286.html>.
Regarding the experiment conducted on the students with and without SAD, you stated that the longer secretion durations were particularly detrimental to one’s health and I disagree with this answer. Melatonin by itself is actually very good for you for a number of different reasons, it is even prescribed to people with sleeping disorders and even offered on the shelf at your general convenience store. I think you are getting confused about the increase of melatonin and the lack of vitamin D we get during the winter because of the small amount of daylight. Vitamin D, which is connected to efficient energy and cellular production) is the factor that connects the lethargic feeling we get in winter–which in turn makes us feel depressed and for lack of a better description, blob-like.
According to NYU Langone Medical Center, those who experience SAD might consider vitamin D as a way to alleviate their wintertime blues.
I also can relate to this study because I always feel more depressed and have less energy in the winter than the spring or summer. This article states that people who feel this way are not alone. This is because humans are naturally programmed to rest when it’s dark and be productive when it’s light outside. However, when day light savings comes around every year, we find ourselves with dark at 5 o’clock. Also serotonin, the hormone responsible for happiness, is prominent on sunny days.
Personally, I have always felt the effect the weather has on my mood. When I wake up and the sun is shining on a crisp fall day, I’m instantly energized and ready to go about my day. In contrast, when I wake up to pouring rain and little sunlight on a cloudy, winter day, I usually just go back to sleep. Clouds, precipitation, and darkness all seem to drain the energy out of me and spoil my mood.
I found your research on light therapy to be really interesting. Could people diagnosed with SAD be cured simply by moving to a warmer climate with more sunlight? Could the real cure be a trip to the south? This also leads me to ask whether people farther away from the equator tend to be unhappier than their counterparts living in the sun year-round.