How Sleep Plays A Role In Seasonal Affective Disorder

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Seasonal affective disorder, or SAD, is a type of major depressive disorder that’s characterized by experiencing depression at certain times of the year. According to Psychology Today, around 10 million Americans suffer from SAD.

The most common SAD pattern is for people to feel depressed during the autumn or winter and improve in the spring, but there are some instances of summer seasonal depression, too.

Symptoms of SAD include low energy levels, trouble sleeping, oversleeping, feeling depressed for most of the day almost every day, appetite or weight changes, feeling hopeless or lost, and having difficulty concentrating.


According to the Mayo Clinic, we don’t know exactly what causes SAD, but one theory is that it’s linked to circadian rhythms.

“The reduced level of sunlight in fall and winter may cause winter-onset SAD,” the Mayo Clinic website explains. “This decrease in sunlight may disrupt your body’s internal clock and lead to feelings of depression.”

Psychology Today explains another theory: “One theory is that it is related to the amount of melatonin in the body, a hormone secreted by the pineal gland. Darkness increases the body’s production of melatonin, which regulates sleep. As the winter days get shorter and darker, melatonin production in the body increases and people tend to feel sleepier and more lethargic.”

Related: The Importance Of Sleep

Both of these theories could explain why oversleeping is such a common symptom of SAD.

There are a number of treatments for SAD, depending on the individual’s needs and how severe the issue is. Antidepressant medication, counseling, Vitamin D supplements, and light therapy are common treatment tools.

During light therapy, the patient sits or works near a light therapy box, which emits light that is similar to natural outdoor light. The idea is that this light affects chemicals in the brain, suppressing the melatonin that makes you sleepy.

“Generally, most people with seasonal affective disorder begin treatment with light therapy in the early fall, when it typically becomes cloudy in many regions of the country,” Mayo Clinic says. “Treatment usually continues until spring, when outdoor light alone is sufficient to sustain a good mood and higher levels of energy.”

If you think you have SAD, talk to your doctor about your symptoms and ask what treatments they would recommend. If you simply find yourself oversleeping in the winter season but don’t have depressive symptoms, it’s still worth checking in with a medical professional to investigate what’s causing you to oversleep.

Featured image: SergeyIT/Shutterstock

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Joe Auer

Joe Auer is the editor of Mattress Clarity. He mainly focuses on mattress reviews and oversees the content across the site.

He likes things simple and take a straightforward, objective approach to his reviews. Joe has personally tested nearly 250 mattresses and always recommends people do their research before buying a new bed. He has been testing mattresses for over 5 years now, so he knows a thing or two when it comes to mattress selection. He has been cited as an authority in the industry by a number of large publications.

Joe has an undergraduate degree from Wake Forest University and an MBA from Columbia University.