How Common Is Seasonal Affective Disorder, Really?

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How common is seasonal affective disorder (SAD)? This is a common question this time of year, now that the days are shorter and the nights longer. If this dreary winter weather has you feeling blue, there's a chance you may be suffering from SAD — here's how to tell and what you can do to feel better. 

What is seasonal affective disorder? 

Seasonal affective disorder is a condition that causes a person to experiencea  dramatic mood swing during the changing of the seasons. Okay, so you get sad when summer's over — it happens to everyone, right? If SAD sounds made-up to you and you're asking yourself, "Is seasonal affective disorder real?" the answer is yes. While the CDC does not consider SAD its own condition — rather, it's a type of depression — there are still troubling symptoms you need to be on the lookout for.

While SAD most commonly occurs during the fall and winter, it's possible for it to happen during the summer. This type of SAD manifests itself in different ways than typical SAD.

What are common seasonal affective disorder symptoms? 

These are the symptoms the CDC says to look for:

For winter patterns of SAD:

For summer patterns of SAD:

What causes seasonal affective disorder? 

The cause of SAD is not yet known, but experts believe there is a biological component. People diagnosed with SAD have issues regulating the production of serotonin — a so-called "happy hormone." They also produce less vitamin D, which is believed to play a role in serotonin activity. A 2013 study in The British Journal of Psychiatry found results consistent with many other studies that low levels of vitamin D is associated with depression.

The CDC also says people with SAD overproduce the hormone melatonin, which plays a role in the sleep process. An overproduction of melatonin can result in feelings of lethargy and sleepiness, affecting a person's circadian rhythms

How common is seasonal affective disorder? 

According to the American Academy of Family Physicians, about four to six percent of the population has SAD. Another 10 to 20 percent might have a mild version. 

Women are four times more likely than men to be diagnosed with SAD, the CDC says. Young adults and people have a history of depression or bipolar disorder have higher risks of developing SAD, as well as those who live far from the equator where SAD is most commonly diagnosed.

How do I know if I have seasonal affective disorder? 

There are online quizzes you can take to determine if you have seasonal affective disorder, but it's best to see a doctor if after reading the list of common SAD symptoms you recognize some of them in yourself.

How is seasonal affective disorder treated? 

If you have been diagnosed with SAD, there are several treatment options that can be used separately or in conjunction. 


Because serotonin is thought to be a factor in SAD, doctors can prescribe selective serotonin reuptake inhibitors (SSRIs), which are a class of drugs that are commonly used as antidepressants. Like all medications, SSRIs have their own side effects, and you can talk to your doctor if you have any questions or concerns.

Light therapy

Seasonal affective disorder lamps ($50.33, Amazon) have been used to combat SAD since the 1980s. Sitting in front of an artificial light for 20 to 60 minutes during the day could help make up for the lack of exposure to natural light in fall and winter.


Using cognitive behavioral theraphy (CBT) techniques, patients are asked to use a process called behavioral activation to identify negative thoughts and replace them with positive ones. The point of behavioral activation is to help a person to recognize fun activities that will help them cope during the winter months.

Vitamin D supplementation

Evidence is mixed regarding whether vitamin D supplementation on its own is enough to cure SAD symptoms. A recent August 2014 study published in the journal BMC Research Notes could not demonstrate the affects of vitamin D on SAD. 

How can I help myself today?

Seasonal affective disorder shouldn't ruin your fall and winter — especially when there are so many heartwarming holidays coming up. Be honest with yourself if you think you need help; there's nothing wrong with asking for a hand. If you have any other questions regarding SAD, don't hesitate to make an appointment with a trusted physician. 

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