SAD: Is Seasonal Affective Disorder Affecting You?

mental health Nov 30, 2020

Late fall is here and winter will soon be settling in and with it the onset and progression of Seasonal Affective Disorder (SAD). Although the dark days and cold weather do tend to have a mood-dampening effect, it is important to recognize when it is more than just the winter blues.

Seasonal Affective Disorder (SAD) is a type of depression following a cyclical pattern associated with the onset of fall and winter. People can experience the following symptoms:

  • low mood (ie. feeling blue, sad, hopeless)

  • having a loss of interest in things that once brought pleasure

  • lack of appetite or overeating

  • sleep disturbances

Diagnosis of SAD is four times more likely in females than males, and it is more frequently diagnosed in those who live further from the equator - as East Coast Canadians this absolutely impacts us.

The mechanism of action responsible for this condition is still not understood, but it has been found that those who experience it produce more melatonin. This plays a large role in the experience of fatigue and lethargy.


There have also been studies to suggest disruption of serotonin (5-hydroxytryptamine or 5-HT), the neurotransmitter which plays a role in mood regulation. In one study, people with SAD produced more SERT, a protein that supports serotonin transport and is more abundant in winter months than summer where sunlight generally keeps SERT levels naturally low. As sunlight diminishes in the fall, a corresponding decrease in serotonin activity also occurs. Higher SERT levels lead to lower serotonin activity which can result in depression. Serotonin impacts the following: 

  • Mood: Known as our "feel-good" hormone and initiates fight-or-flight, and directly impacts levels of mood, happiness, and anxiety.
  • Digestion: Fun fact: most of our serotonin is created by enterochromaffin (EC) cells in the lining of our GI tract, playing a role in the gut-brain axis. Read up on our post about mood boosting foodsSerotonin also impacts nausea - if we consume something that aggravates the digestive tract the gut produces serotonin to deal with the irritant through diarrhea or stimulating nausea in the brain. 
  • Bone mass and density: Research is mixed in this regard but it is worth noting that there is some research behind the effects of serotonin synthesis on bones. There are correlations between high levels of serotonin present in bones and an increased risk for osteoporosis.



Vitamin D: Research correlates low serum Vitamin D levels with depression and that deficiency plays a role in the onset of seasonal affective disorder. Vitamin D regulates genes which are responsible for release of some neurotransmitters. Neurotransmitters are chemicals in the brain that play a role in our mood regulation. Research on SAD suggests vitamin D deficiency is linked to a decrease in the production of serotonin.

St Johns Wort: relevant medicinal properties are nervine tonic (modulating stress and anxiety) and mood balancing. Research shows St. Johns Wort increases the amount of serotonin in the body similarly to pharmaceutical drugs (such as SSRIs) that are used to treat mood. Its mechanism of action is to act on specific serotonin receptors in the brain in order to prevent the reuptake of serotonin. Additionally, a phytochemical called hypericin found in St. Johns Wort can cross the blood-brain barrier and increase dopamine levels - remember that dopamine is our happy/pleasure hormone! It is important to discuss the use of St. Johns Wort with a medical professional as it has many herb-drug interactions and contraindications.

  • What is the difference between St. Johns Wort and SSRIs? Pharmaceutical drugs work by one method of action. St. John’s Wort is an herbal intervention that has multiple mechanisms of action that come from using the entire plant (roots, leaves, flower) and helps to balance the body and mind simultaneously.

Exercise: There's a reason that you feel so great after a workout! When you exercise you release endorphins. Physical activity is not only protective for your health but it also has been shown to improve mood. It can be an opportunity for social interaction and connection, or an opportunity to spend some time to yourself which can help nourish your body and mind. Studies show movement stimulates our serotonin system and increases the production of dopamine. The result is an antidepressant boost in your emotional well-being. It can be difficult to motivate an exercise routine during this time, but shifting your perspective on what physical activity is for you is very helpful. Re-evaluate the kind of exercise you need right now and find an activity you can commit to.

Nutrition: circling back to mood foods for a moment - the foods we eat affect our gut-brain axis as well as encourage the production of serotonin and other balancing hormones that impact our mood and can help fend-off SAD. 

  • Endorphins: consume spicy foods to encourage release
  • Dopamine: consume yogurt, beans, almonds, avocado and eggs (a great reason to have avocado toast more often!)
  • Serotonin: increase levels with foods high in the amino acid L-tryptophan and omega-fatty acids such as fish (halibut, salmon), eggs, turkey, sesame, chia, and pumpkin seeds
  • General hormone release and balance: encourage this process with probiotic foods such as kimchi, sauerkraut, kombucha, miso and tempeh

Light therapy: This treatment is rooted in the understanding that reduction in sunlight on our skin can trigger the onset of SAD, and consists of exposure (20-60 mins daily) to light at wavelengths that promote vitamin D production. Research supports that light therapy decreases the impact of SAD and improve mood and energy levels.

How to optimize the effect of the light box/light therapy:

  • Light should be 10,000 lux
  • Full spectrum white light that filters UV light
  • Positioned at eye level or higher
  • Kept at an angle not positioned directly in your eyes
  • Exposure should be a minimum of 20 minutes or up to 60 minutes a day depending on your needs

Exposure to this light triggering Vitamin D production helps increase serotonin production and endorphins!


Book today if you're feeling the effects of reduced sunlight and winter being just around the corner, and want to help maintain balance with the seasonal fluctuations!

Moncton: email [email protected] or browse services and book here!

Charlottetown: email [email protected] or browse services and book here! 



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