Seasonal Affective Disorder

Autumn has officially arrived and this Vancouver weather couldn’t make that any more apparent. Welcome back, rain and lush foliage! While our city’s thirsty soil is greeting the rain with open arms, the colder weather, shorter days, and grayer skies are cause for seasonal affective disorder, or SAD, in nearly 20% of the population.

SAD is a type of depression that is related to the change in seasons, usually occurring in the fall/winter and remitting in the spring/summer. While researchers are not exactly sure what causes SAD, it has been linked to a lack of sunlight. Shorter days with less light may increase melatonin, which will deregulate sleep-wake cycles and circadian rhythms, and decrease serotonin production, which can affect mood. Symptoms of SAD may include:

  • Feeling sad, moody, or anxious.
  • Inability to handle stress.
  • Losing interest in usual activities and physical contact.
  • Weight gain and carbohydrate cravings.
  • Excess sleep with extreme fatigue.
  • Trouble with concentration.

Unlike other forms of depression, the standard medical recommendation and first line of defense for SAD is light therapy (phototherapy). Sunlight plays a critical role in regulating melatonin and serotonin levels, thus replacing it can greatly impact the effects of SAD. Aside from a high quality light box, “dawn-simulating” alarm clocks are designed to get brighter and brighter in the morning to naturally imitate the rising sun. Full spectrum light bulbs are also an efficient way to increase light exposure.

In addition to light therapy, there are several herbs, supplements, and lifestyle modifications that decrease the symptoms of SAD.

  • Vitamin D: Especially in cities like North Vancouver where sun in sparse in the fall and winter, supplementing with vitamin D and maintaining optimal levels is critical. Vitamin D is required for many of the body’s functions, including mood regulation. Sunlight is necessary to convert vitamin D to its’ active and usable form. While blood levels can and should be drawn to check baseline levels, most North Vancouverites who are 18 and older can safely take 5000 IU of vitamin D each day. Vitamin D is fat soluble, so taking it in conjunct with a healthy fat will optimize absorption. Vitamin A, zinc, and boron are important cofactors also positively impact vitamin D absorption in the body.
  • Exercise: physical activity is a natural way to improve mood.
  • Omega-3: krill and other fish oil omega-3 fatty acids are linked to enhanced emotional health. High quality fish oils with both EPA and DHA should be considered. Krill oil, versus other fish oils, contains phosphate groups that improve bioavailability and absorption. Therefore, lower doses of krill oil can be taken – typically between 1 and 3 grams.
  • Avoid grains and sugars: simple carbohydrates can increase insulin resistance, which is linked to depression, as well as temporary spikes in energy that result in subsequent exhaustion.


Always consult with a healthcare provider before starting or stopping any medication or supplement. Please, feel free to contact us with any questions or concerns.