Seasonal Affective Disorder, Sleep & Light Therapy

If you are feeling a little extra down this year, you’re not alone. But are you experiencing Seasonal Affective Disorder?

It’s that time of year again; the time just after the holidays when the days are shorter, we get less light and spring blooms are three whole months away. This time of year can be especially tough for east coasters—and in 2021, the pandemic is definitely not helping anybody. If you are feeling the blues lately, you are most definitely not alone. However, it could be more than just the blues. 4-6% of Americans experience what is called Seasonal Affective Disorder (SAD). SAD can impact mood and can also disrupt your sleep. Because we know SAD is hitting especially hard this year, we thought it would be a good time to explore the science behind light therapy, a common treatment for SAD. 

What exactly is Seasonal Affective Disorder and why do people experience it?

More than simply feeling down, individuals with SAD experience feelings of depression every day around the same time of year. SAD results in low energy, issues with sleeping, shifts in appetite and weight, feelings of hopelessness, disinterest, guilt and hopelessness. Often, individuals suffering from SAD also become especially irritable between early winter and springtime. Women and young people are most susceptible to SAD.

While there isn’t one single cause for it, there are a few specific reasons researchers believe people experience SAD: 

  • Disruption of the circadian rhythm: When the seasons change, our routines shift. The lack of light and shorter days often disrupt our biological clocks leading to feelings of tiredness and depression.
  • Increased production of melatonin: Due to the sun sinking earlier, our bodies can be cued to start getting ready for bed which spurs the production of melatonin making us more tired earlier in the day.
  • Vitamin D deficiency: The decreased amount of light in the wintertime impacts the amount of Vitamin D people can take in and Vitamin D is said to be linked with serotonin activity, a key hormone for mood regulation. Decreased serotonin levels can have physical and psychological consequences, causing depressive symptoms. 

Seasonal Affective Disorder & Sleep 

Since SAD is caused by two key sleep-oriented consequences of seasonal change (disrupted circadian rhythm and increased melatonin production), sleep issues are a top symptom. SAD can cause excessive sleepiness during the day and trouble waking up in the morning. But SAD-related sleep problems are not limited to excessive sleep—it can even cause nightmares. And, while sleeplessness is often associated with depression, too much sleep can also exacerbate depressive feelings.

Treatment: SAD Lamps & Light Therapy

Light therapy or phototherapy is a common treatment for SAD. The goal with this type of therapy is to essentially reverse the effects of the light deficit brought on by the winter months by bringing more light into your day. Delivering high intensity white light—which mimics natural light— SAD lamps help stimulate serotonin production. In order for treatment to be effective, the light intensity is key; it is recommended that patients use a 10,000-lux box for 10 to 15 minutes per day at first, gradually increasing to 45 minutes 1–2 times per day. When using a lightbox, one must keep their eyes open as the treatment is absorbed through the eyes and not the skin. 

When looking for a light box or SAD lamp, intensity of the light as well as UV protection for eyes are two key factors to consider. It is also important to speak with a medical professional before undergoing light therapy at home to ensure you  are a good fit for the treatment. That said, light therapy is proven to be a fairly effective remedy for SAD, individuals undergoing treatment often feel positive effects within 1-2 weeks of treatment. 

Another recommended approach to SAD is cognitive behavioral therapy, a method of talk therapy that challenges cognitive distortions and promotes behavioral changes. Additionally, if  you think you might be experiencing SAD symptoms, getting outside for walks on a regular basis, sitting near windows and finding other opportunities to bring real natural light into your day can also make an immediate difference in your mood. 

While SAD can be debilitating, the upside is that it does typically resolve itself when the seasons change. However, treatment can make the winter months much more joyful—saving sufferers several months of discomfort. If you or a loved one are suffering, talking with a professional is a great place to  start. 

Read more here, here, here, here, here and here 


The information in this article is not intended to replace the advice of a professional, serve as a diagnosis or substitute treatment. If you or a loved one are experiencing symptoms of depression or have any other mental health concerns, it is important to seek the support of a mental healthcare provider right away and if you are experiencing a crisis, the National Suicide Prevention Lifeline can be  reached at 800-273-8255.