Tis the season for significant drops in temperature, shorter days, and feeling SAD.
By SAD, I mean Seasonal Affective Disorder.
I’ve written about SAD and its effects in the past both in regards to the winter season and the summer time. Seasonal Affective Disorder is a form of clinical depression that kicks off during the late autumn and winter thought to be caused by the decrease in daylight .
While I’m not clinically depressed, I feel moodier, bitchier, and less pleasant as the days go by. This signals to me the that another segment of the ‘Winter Blues’ has commenced as I detect the changes in my mood and behavior due to the cold weather and shortened daylight cycle.
Here’s a quick rundown of SAD :
Other symptoms include:
- Feelings of Sadness and Despair
- Crying Spells
- Body Aches
- Lack of Motivation
- Loss of Sex Drive
For those who appreciate a good visual aid:
Although we know what it is, I have long pondered why. Science tells us it has to do with the amount of sunlight a person receives and the circadian clock and how these changes affect our serotonin levels. Finally, Vanderbilt biologists have confirmed this long standing theory.
Researchers found an interesting predetermining potential factor for SAD: when you were born.
Researchers focused on the Dorsal Raphe Nucleus located in the Midbrain, it is the area that contains specialized neurons that control serotonin levels throughout the brain .
They found that the day/night cycle in which an individual is born into can have a long lasting effect in the activity levels of neurons here.
The Dorsal Raphe Nucleus is linked to the master biological clock and responds to melatonin, a regulatory neurotransmitter that controls physiological functions like sleep, blood pressure, and seasonal reproduction.
In order to test this theory, researchers conducted the experiment on mice and broke them down into three groups that were born and raised in either a:
- Summer-Like environment with a 16 hour light cycle and an 8 hour dark cycle
- Spring/Fall-Like environment with a 12 hour light cycle and a 12 hour dark cycle
- Winter-Like environment with an 8 hour light cycle and a 16 hour dark cycle
Scientists ensured that the three groups of mice were raised in identical environments other than the light cycle.
To measure for depression, biologists used a forced swim test (no mice drowned as a result of this test since mice can float), where the mice were placed in a pool of water to measure how much time it spent struggling to get out versus how much time it spent floating passively.
It was argued that mice who were depressed would spend less time struggling. Results indicated that their argument was correct: Summer-light cycle mice exhibited lower levels of depression-like behavior compared to the Spring/Fall and Winter groups of mice.
Consistent with behavioral findings, brain analysis of the mice from the three groups showed that serotonergic neurons fire faster in the summer-light cycle mice and had elevated levels of both serotonin and norepinephrine (neurotransmitter that excites serotonergic neurons).
These findings indicate that early life seasonal photoperiods, day/light length, can have enduring effects on the serotonergic neurons. Long photoperiods have been shown to:
- Increase serotonin excitability and firing
- Increase serotonin and norepinephrine levels in the Midbrain
- And during development, has been found to induce a lasting increase in firing rates.
This research article was incredibly fascinating as I can already detect a shift in my mood and perception of life’s happenings. I’m very aware that it is due to the seasonal change and am actively trying to circumvent any serious complications that may result of it. However, this really brought home as to why I, and many others, may experience this alteration as the season changes.
I was born in January in New York City, a very heavy winter-like environment, so I didn’t experience long enough photoperiods during my early months of development. My brain didn’t get a chance to increase its serotonin firing rate therefore, not allowing me to adapt to the darker days as easily as someone born in the summer. Obviously, there are plenty of other factors that come into play but it’s nice that we have found another piece of the puzzle.
As the days become darker and colder, I will be sure to soak up as much daylight as I can, be a stickler about my sleep schedule and overall routine, and pay closer attention to my body. Of course, I will be baking a lot more these days to overcome the crappiness outside – because there is nothing a delicious piece of chocolate cake or moist vanilla cupcake can’t solve. So if you have any requests I’ll be sure to 1) bake it 2) take a picture of me eating it and 3) send it your way.