What Is Seasonal Depression?

This past winter I found myself leaving my room less and less as the days went on. My room would get progressively messier, and my motivation to do anything at all seriously declined.  The cold temperatures kept me bundled up in bed watching TV throughout the day and night, and I even stopped using my desk for school work. Every morning I wanted to sleep in more because I had no energy to do much else, but I didn't even realize how much the change in seasons affected my daily routine.

Do you also find yourself feeling down during the colder months? Or find it harder to get out of bed and motivate yourself? Seasonal affective disorder (SAD) also referred to as seasonal depression may be the root of your issue. Around 5% of adults in America have this seasonal affective disorder, so you're not alone. 

Get the treatment you need for SAD

Yes, most people get upset when summer comes to an end and we have to return to our normal lives, but prolonged sadness during the winter season is a real issue. People with SAD experience a type of depression that is related to a change in season, which typically begins and ends around the same time each year. SAD is different from regular depression because the depressive symptoms are only in effect during a specific season, whereas people with major depression experience them year-round. There also happen to be two types of SAD, winter-onset, and summer-onset. However, winter-onset SAD is much more common.

What are the symptoms of seasonal depression? Well, winter-onset SAD and summer-onset SAD differ from one another. Oversleeping, lack of energy, extreme fatigue, weight gain (carbohydrate cravings), anxiety, irritability, thoughts of suicide, and more are symptoms of winter depression. While summer depression include insomnia (trouble sleeping), agitation and restlessness, anxiety, weight loss and decreased appetite, episodes of violent behavior, and more.

Fatigue (Getty Images)

Oversleeping (Getty Images)

While the causes of SAD are still being studied and questioned, serotonin and melatonin production in our bodies seem to be key factors. As the summer comes to an end with fall and winter approaching, the days get shorter, resulting in a decrease in sunlight. With less exposure to the sun, some people's circadian rhythm (internal clock) shift, causing troubles in their mood regulations. The production of melatonin, which causes tiredness, is driven by this decreased exposure to light. Our eyes see sunlight and send a signal out to the suprachiasmatic nucleus which then signals the pineal gland to inhibit the secretion of melatonin to wake our bodies up. However, in the winter it is oftentimes dark when we wake up, so our bodies are tricked into secreting more melatonin to sleep. An overproduction of melatonin causes those feelings of lethargy and depressive symptoms. This is why countries like Canada and Norway that are closer to the poles have a higher percentage of people with SAD.

Circadian Phase Shift (source)

Physiology of Melatonin Secretion (source) 

Sunlight also regulates the production of serotonin, a neurotransmitter that stabilizes our mood, and low levels of serotonin are generally linked to depression. One study found that people with SAD had 5% more SERT, a protein involved in the transport of serotonin, during the winter months. Higher levels of SERT lead to decreased serotonin activity which causes depressive symptoms. Another study by researchers at the Medical University of Vienna compared how the brain removes serotonin in 73 people with untreated SAD and 70 people without SAD; they found that those with SAD had a faster rate of removal of serotonin causing their serotonin levels to drop below average. 

If you're worried you may have SAD do not fret! There are several ways to manage the symptoms. The best kind of treatment is light therapy; the use of a lightbox for around 30 minutes allows the internal clock to readjust by mimicking natural light. Along with light therapy, there are antidepressant medications called selective serotonin reuptake inhibitors (SSRIs) that treat depression by increasing serotonin levels in the brain. Doctors also recommend spending more time outside with exposure to sunlight, exercising regularly, eating healthier, sleeping regularly, and talking therapies to regulate mental health. And always remember, it is perfectly okay and encouraged to ask for help if you're feeling down.