Winter is coming, and so too are shorter days and longer periods of darkness. For a sizable percentage of people (~3% of the Canadian population1), this change to our environment can bring about a seasonal form of depression called Seasonal Affective Disorder, SAD. Those who experience SAD experience an onset of clinical depression in the fall season, which spontaneously improves in the summer, a cycle that usually repeats for at least two calendar years in succession. Interestingly, the symptoms of SAD are not typical of non-seasonal depression.2 Depressed mood, loss of interest in activities, and withdrawal from social interaction is common to both, but where typical depression usually includes insomnia, anxiety and reduced food intake, SAD is characterized by hypersomnia, carbohydrate craving and increased body weight. The symptoms look superficially like seasonal rhythms in animals as they prepare to hibernate.
In fact, many of the same biological mechanisms which prompt the onset of hibernation in animals like bears are similar to the processes which give rise to SAD in humans. This is because most organisms have internal body clocks which track daily and annual cycles in the external world. Our body clocks, for example, are capable of tracking how long the sun is present each day. While we don’t yet fully understand why this process affects mood, we know that SAD is associated with day length because data from different American states reveal that the incidence of SAD are higher in more northern states.3 This is also true of the ‘winter blues’, or sub-clinical SAD. We also know that the issue is in terms of day length and not the amount of sunshine a location gets because Calgary (~51° N) has much more winter sunshine than Vancouver (~49° N) but similar daylengths and population rates of SAD. This is particularly important information for us Canadians who live north of the 49th parallel. We may get plenty of sun, but we still experience shorter days.
So, as we get less daytime during these seasons, is it possible to trick our body clocks into thinking the days are longer?
Remarkably, one of the most effective remedies for SAD is bright light treatment. Introducing bright light in the Fall and Winter can prevent or reverse SAD, with roughly 2/3rd of SAD patients responding to the treatment4. The research indicates that it is as effective an antidepressant as any pharmaceutical used to treat SAD and when used correctly is accompanied by relatively few possible side effects. Importantly, however, bright light therapy may trigger mania in individuals with bipolar disorder5, so please consult with your doctor before considering the treatment. The minimum effective dose is approximately 2500 lux, which is about the intensity of sunrise outdoors.6 Bright light treatments, however, will often exceed 10,000 lux. Indoor, room lighting typically emits 500 lux and is thus an ineffective treatment. Those susceptible to SAD can purchase bright light-emitting visors or, alternatively, there are bright light lamps which allow one to sit or work in an environment containing ambient day-time levels of light. These devices can also be used strategically to ease certain sleep disorders and help realign one’s body clocks during jet lag.7
Because many of the symptoms of Major Depression and SAD are shared and the two disorders are often comorbid, traditional psychotherapy is also a highly effective treatment for seasonal depression.2 Research using group-based cognitive-behavioural therapy (CBT), for example, has demonstrated antidepressant effects which nearly mimic 30 minutes of 10,000 lux bright light treatment.8 Health professionals who utilize CBT teach skills to those suffering from various forms of depression which help to change their perceptions of the world.9 Cultivating emotional regulation, developing personal coping strategies, and learning to disrupt patterns of negative thoughts and actions are key constructs of CBT. Bright light treatment and psychotherapies like CBT may be used alongside one another, as well as in conjunction with other therapies like medication or mindfulness practices. Research also suggests that people whose depressive symptoms look more like the ‘winter blues’ than seasonal depression should improve their diets by limiting starches and sugars, exercise frequently, manage stress (especially around the holidays), increase social contact and connection, and spend more time outdoors.10
Finally, vitamin D, an essential building block for our bones and muscles, is in short supply in the Canadian Fall and Winter months. A deficiency of vitamin D has been associated with depressive symptoms and some research suggests that taking vitamin D before winter darkness sets in may help prevent symptoms of SAD.11 During the winter months, those living roughly 33 degrees north or 30 degrees south of the equator synthesize very little, if any, vitamin D.12 People beyond these latitudes rely primarily on eating fish and egg yolk or taking nutritional supplements to get the vitamin D needed.13 It is important that most of us, and perhaps especially people experiencing SAD, ensure that we have sufficient levels of vitamin D during these darker months. Thankfully, the Canadian government acknowledges this problem and mandatorily requires that products like cow’s milk, margarine, and calcium-fortified beverages have vitamin D added to them.14 Planning a mid-winter vacation may be valuable for its increased light exposure and onset of vitamin D synthesis, and who doesn’t like taking a vacation as a form of treatment?15
Thankfully, there are multiple options for Seasonal Affective Disorder which allow for more personalized treatment plans. If you’re feeling blue this Fall and Winter, Alongside You offers an abundance of counselling and well-being services that can help you if you identify with any of the discussion above regarding SAD.
If we can be of help to you, please don’t hesitate to ask. This is why Alongside You exists – because we believe that everyone is worth it. Feel free to contact us to see how we can help!
Adam Manz recently graduated from Simon Fraser University with a Bachelor of Arts majoring in Psychology. He is currently pursuing a master’s degree in clinical psychology while maintaining a love for meditation, podcasts, and hiking. Adam is volunteering with us here at Alongside You and we’re glad to have him on board!
1Body and Health Canada. (2019). Seasonal affective disorder. Retrieved from https://bodyandhealth.canada.com/healthfeature/gethealthfeature/seasonal-affective-disorder.
7Burgess, H. J., Crowley, S. J., Gazda, C. J., Fogg, L. F., & Eastman, C. I. (2003). Preflight adjustment to eastward travel: 3 days of advancing sleep with and without morning bright light. Journal of Biological Rhythms, 18(4), 318–328. doi: 10.1177/0748730403253585
9Canadian Mental Health Association. (2013). Seasonal affective disorder. Retrieved from https://cmha.bc.ca/documents/seasonal-affective-disorder-2/.
5Chan, P. K., Lam, R. W., Perry, K. F. (1994). Mania precipitated by light therapy for patients with SAD (letter). Journal of Clinical Psychiatry 55:454
4Golden, R. N., Gaynes, B. N., Ekstrom, R. D., Hamer, R. M., Jacobsen, F. M., Suppes, T., … Nemeroff, C. B. (2005). The efficacy of light therapy in the treatment of mood disorders: A review and meta-analysis of the evidence. American Journal of Psychiatry, 162(4), 656–662. doi: 10.1176/appi.ajp.162.4.656
13Health Link BC. (2019). Food sources of calcium and vitamin D. Retrieved from https://www.healthlinkbc.ca/healthlinkbc-files/sources-calcium-vitamin-d.
3Horowitz, S. (2008). Shedding light on seasonal affective disorder. Alternative and Complementary Therapies, 14(6), 282–287. doi: 10.1089/act.2008.14608
14Janz, T., & Pearson, C. (2015). Health at a glance: Vitamin D blood levels of Canadians. Retrieved from https://www150.statcan.gc.ca/n1/pub/82-624-x/2013001/article/11727-eng.htm#n2.
11Kerr, D. C., Zava, D. T., Piper, W. T., Saturn, S. R., Frei, B., & Gombart, A. F. (2015). Associations between vitamin D levels and depressive symptoms in healthy young adult women. Psychiatry Research, 227(1), 46–51. doi: 10.1016/j.psychres.2015.02.016
10National Health Services. (2018). Treatment of seasonal affective disorder (SAD). Retrieved from https://www.nhs.uk/conditions/seasonal-affective-disorder-sad/treatment/.
8Rohan, K. J., Mahon, J. N., Evans, M., Ho, S.-Y., Meyerhoff, J., Postolache, T. T., & Vacek, P. M. (2015). Randomized trial of cognitive-behavioral therapy versus light therapy for seasonal affective disorder: Acute outcomes. American Journal of Psychiatry, 172(9), 862–869. doi: 10.1176/appi.ajp.2015.14101293
12Stewart, A. E., Roecklein, K. A., Tanner, S., & Kimlin, M. G. (2014). Possible contributions of skin pigmentation and vitamin D in a polyfactorial model of seasonal affective disorder. Medical Hypotheses, 83(5), 517–525. doi: 10.1016/j.mehy.2014.09.010
6Tam, E. M., Lam, R. W., & Levitt, A. J. (1995). Treatment of seasonal affective disorder: A review. The Canadian Journal of Psychiatry, 40(8), 457–466. doi:10.1177/070674379504000806
15Targum, S. D., & Rosenthal, N. (2008). Seasonal affective disorder. Psychiatry (Edgmont), 5(5), 31–33.
2The National Institute of Mental Health. (2016). Seasonal Affective Disorder. Retrieved from https://www.nimh.nih.gov/health/topics/seasonal-affective-disorder/index.shtml.