While the winter months begin, the sky is not the only thing getting cloudy as many individuals produce symptoms of seasonal depression.
Seasonal depression, formally known as Seasonal Affective Disorder (SAD), is “a form of recurrent depression that typically starts in late fall or early winter and resolves in the spring or summer,” according to Yale Medicine.
SAD is more severe than just “winter blues,” and can be characterized by symptoms similar to depression, including feelings of hopelessness, loss of interest in hobbies or activities, and changes in sleep or appetite.
It is always important to consult a healthcare professional to learn more about these symptoms and what treatments may be available if diagnosed.
As individuals living in a heavily winter-weathered area, we may want to learn about SAD and understand the neurological mechanisms behind this disorder. Although there is still more research to be done, a few projects have identified important brain regions and signals responsible for SAD.
Individuals with SAD tend to have reduced levels of serotonin, a chemical messenger from the brain responsible for mood regulation. This reduction may be due to the reduced amount of sunlight available during the winter months, according to the National Institute of Mental Health (NIMH), given that “sunlight affects levels of molecules that help maintain normal serotonin levels.”
Beyond serotonin, sunlight also impacts melatonin levels in the brain. Melatonin is a neurotransmitter that regulates sleep levels. A decrease in sunlight leads to an increase in melatonin production, and therefore an increase in sleepiness and lower energy.
Individuals who live further north are more likely to be diagnosed with SAD. This is due to the earth’s tilt and revolution around the sun. The Northern Hemisphere receives much less sunlight because it is tilted away from the sun during the winter months.
Specific brain regions may play a role in seasonal depression. A 2015 Vanderbilt University study located a small region of the midbrain called the dorsal raphe nucleus that may play a part in depressive effects triggered by the seasonal light cycle. The dorsal raphe nucleus houses many of the brain cells responsible for serotonin levels, further emphasizing the NIMH’s association of serotonin levels with Seasonal Affective Disorder.
Additionally, when there is a change in daylight, an individual’s biological clock shifts. This clock, also known as the circadian rhythm, regulates an individual’s sleep-wake cycle. Mood, hormones and sleep are affected when there is an imbalance in this cycle, all of which are possible contributors to general and seasonal depression.
Although a generalization, the NIMH believes SAD begins around young adulthood, the age of most college students. Still, there is much more work to be done in understanding what Seasonal Affective Disorder is and the mechanisms behind it.
SAD can be very serious and become prolonged, so it is important to recognize potential signs of SAD in yourself and your loved ones. Experts recommend consulting a health professional to learn more about these symptoms and what treatments may be available if diagnosed.
