Seasonal Affective Disorder: Health Experts Explain Why We Get Mood Disorder During Winter

Seasonal affective disorder (SAD) is a form of depression that strikes around the same time every year – late fall or early winter. According to mental health specialists, the mood disorder is triggered by lack of sunlight.

When winter approaches and the days get shorter, the human body reacts to the reduced light conditions by producing a protein called SERT. This protein reduces the level of serotonin in our system, which leads to feelings of depression and sadness.

“Light affects the amount of serotonin in the brain, which is a neurotransmitter that helps regulate our mood,” David Asensio, M.S., a neuroscientist and neuropsychologist, told SELF. “Since SAD is related to the amount of light that our bodies receive, it is understandable that the months of December, January, and February would generally be the most common to experience symptoms.”

With the greater amount of sunlight exposure in the summer, the amount of SERT produced by the body is reduced and serotonin increases, Asensio added.

Seasonal affective disorder or the winter blues is caused by lack of sunlight.
Seasonal affective disorder (SAD), or winter depression, is a mood disorder related to the change in the seasons and lack of exposure to daylight. [Image by Astrid Riecken/Getty Images]

Sunlight is vital to the body’s natural ability to produce vitamin D, an essential nutrient that also plays a part in serotonin activity. The lack of sunlight in the winter adversely affects this process and health experts often associate lower levels of this essential nutrient with depression symptoms.

People generally start to feel mood changes associated with seasonal affective disorder around Labor Day. By October, the symptoms get worse and are most severe right after the holidays. Some people experience SAD after daylight saving time ends.

Seasonal affective disorder disturbs people in different ways and symptoms can range from mild to severe. While experiencing a minor case of the “winter blues” is quite common, you may be suffering the effects of SAD if you experience at least four of the following warning signs.

  • Feeling less energetic
  • Needing more sleep
  • Craving sweets and starches more than before
  • Gaining weight
  • Feeling sad and down in the dumps
  • Becoming less effective at work and activities
  • A desire to withdraw socially

Women are far more likely to be affected by SAD than men. Additionally, seasonal affective disorder is more common in people living far away from the equator. While only one percent of the population in Florida experience symptoms of SAD, nine percent are diagnosed with it in Alaska.

Seasonal affective disorder can significantly influence a person who has already been diagnosed with another mood disorder, making both conditions worse. Young adults and people with a family history of depression are also inclined to developing SAD in the winter.

Psychiatrist John Sharp, M.D. says seasonal affective disorder can be serious, but typically isn’t as devastating as clinical depression.

“With major depression, some people get so depressed they feel worthless or like there’s no point in going on. SAD is bad enough to be clinically relevant, and it can make it impossible to do as much as you normally would do or get as much enjoyment back from what you’d expect would be meaningful, fun, or fulfilling. It’s subtle in a way but it’s insidious.”

Getting relief from the symptoms of seasonal affective disorder can be as easy as increasing exercize.
Individuals suffering from seasonal affective disorder can find some relief using light boxes and vitamin D supplements. [Image by Bruno Vincent/Getty Images]
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Since seasonal affective disorder is linked to lack of light in the winter, getting more light – natural and artificial – may be an effective treatment.

“Intense artificial light acts as an antidepressant and is able to reduce the symptoms of SAD,” says Asensio.

To replace the limited amount of sunlight in the winter, some experts suggest using a light box daily during the winter months. A light box device is capable of emitting 10,000 lux of light while filtering out dangerous UV rays.

Other treatments for SAD include vitamin D supplementation and anti-depressants. A psychotherapy technique known as cognitive behavioral therapy can also be used to help replace negative thoughts with more positive ones.

For most people suffering from seasonal affective disorder, some very small changes could alleviate symptoms. Many experts suggest increasing exercise, eating healthy, and staying active will help improve mood and promote an overall sense of well-being.

[Featured Image by Christopher Furlong/Getty Images]