Seasonal Affective Disorder: Treatment with Supplementation

Seasonal affective disorder, a type of recurrent major depressive disorder, affects an estimated 10 million Americans. In part one of this series, we discussed what seasonal affective disorder is, the common signs and symptoms, risk factors, and the use of medication as treatment.

For part two of our three-part series, we will discuss the use of supplements to treat seasonal affective disorder.

Treatment options

The use of supplements is one of our main treatment options commonly used to treat SAD. The other treatments are:

  1. Medication

  2. Light Therapy

  3. Psychotherapy

Vitamin D Supplementation

A biological clue that research has found in regards to what may be one of the causes of seasonal affective disorder is vitamin D deficiency. Unlike other vitamins, vitamin D functions like a hormone. It plays a significant role in serotonin activity, and serotonin is the key neurotransmitters involved with mood, sleep, appetite and digestion.

Daylight is proven to influence nearly every aspect of human physiology: visual, nonvisual ocular input to the circadian clock, and direct skin absorbance (UV light for vitamin D synthesis.

In the winter, vitamin D levels may be suboptimal as a result of a shorter exposure time to sunlight (1). This also supports the notion that people who live further from the equator in either direction (north or south) are at an increased risk of developing seasonal affective disorder.

In a randomized controlled trial comparing vitamin D supplementation to light therapy, all mood questionnaire items were significantly lower after one month of vitamin D supplementation. These correlated with a rise in vitamin D blood levels of 74% (2).

Low and deficient levels of vitamin D have also been linked to other medical conditions including dementia, prostate cancer, severe erectile dysfunction, bone loss, and heart disease. Those who are vitamin D deficient may also be twice as likely to be diagnosed with schizophrenia.

Is vitamin D supplementation right for you?

An estimated 1 billion people worldwide have low levels of vitamin D in their blood (3). Optimal vitamin D levels are considered between 33-80 ng/mL. Those with less than 33ng/mL are considered to be deficient, and less than 10 ng/mL severely deficient.

Your body naturally makes vitamin from cholesterol when your skin is exposed to sunlight. While certain foods such as fatty fish and fortified dairy products are known to contain high amounts of vitamin D, it is difficult to get the recommended daily intake from diet alone as the recommended daily intake for the average adult ranges from 400-800 IU (or 10-20 mcg). Based on the level of vitamin D in your blood, the recommended daily intake may be higher (1,000-2,000 IU).

There are several ways to help increase your levels of vitamin D including diet, safe sun exposure and supplements. However, working to increase your level should be done at the recommendation and under the supervision of a licensed medical professional because it is possible to achieve toxic levels of vitamin D.

When to seek help

Vitamin D levels are not routinely tested for the average, healthy individual. However, if you are experiencing the symptoms of major depression and/or the season-specific depression symptoms, it is important to consult with a medical professional right away. Our care team will work with you to find the most effective treatment option for your individual needs. This may include supplements or a combination of more than of the above treatment methods. Contact us at (646) 606-2663 and our intake coordinator will work with you to match you with the right clinician for your needs.

1 Wirz-Justice A. Seasonality in affective disorders. Gen Comp Endocrinol. 2018 Mar 1; 258:244–249.
2 Gloth FM 3rd, Alam W, Hollis B. Vitamin D vs broad spectrum phototherapy in the treatment of seasonal affective disorder. J Nutr Health Aging. 1999;3(1):5–7.
3 Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357:266–81.