17 May 2017 | Amelia Thornycroft (BMedSci)

Cracking the SADs

Winter has officially arrived, and for many Australians this also brings a case of the winter blues.

SAD is the acronym for Seasonal Affective Disorder, a form of depression that usually begins in autumn, continuing through the winter months, and believed to affect up to 10% of the population. Symptoms include feeling sad or anxious, fatigue, concentration problems, irritability and feelings of guilt and hopelessness.

The role of sunlight

Although the exact cause of SAD isn't clear, a number of studies suggest it may be triggered by lack of sunlight.

One hypothesis is that reduced sunlight exposure interferes with the body's biological clock that regulates mood, sleep and hormones. Another theory is that lack of sunlight causes an imbalance of neurotransmitters such as dopamine and serotonin which regulate mood.

It is well known that vitamin D levels in the body fluctuate with the changing seasons in response to the amount of sunlight. Vitamin D plays part in the synthesis of both dopamine and serotonin, and it is logical that there is a relationship between vitamin D and symptoms of depression.

You may be at a greater risk of vitamin D deficiency if you stay mostly indoors for health, work or other reasons, have naturally dark skin, or avoid the sun for skin protection or due to medical reasons. Where you live is also a factor, and our Tasmanian Medical Laboratory reports that 60% of Tasmanians presenting for the first time for vitamin D testing at the end of winter show deficiency, and on average in any season of the year 44% of Tasmanians are vitamin D deficient.

Combatting SAD

So if you feel you've got a case of the 'sads', then you might want to consider:

  • increasing your exposure to sunlight (NB following safe sun guidelines)
  • increasing dietary calcium
  • increasing physical activity
  • taking a vitamin D supplement

If you're worried you may have a vitamin D deficiency, then finding out is easy with a simple blood test - see our Vitamin D Check for more details.

Try i-screen's Vitamin D Check
Amelia Thornycroft (BMedSci)
Amelia is passionate about Australia's preventive health agenda having worked with some of the world's largest pharmaceutical companies. Amelia moved to Perth 10 years ago where she founded i-screen to democratise pathology and open access to the health data that really matters.
  • Vitamin D and Depression: Where is all the Sunshine? Sue Penckofer, PhD, RN, Joanne Kouba, PhD, RD, Mary Byrn, BSN, RN, and Carol Estwing Ferrans, PhD, RN, FAAN. Issues Ment Health Nurs. 2010 Jun; 31(6): 385–393. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908269/
  • Seasonal Affective Disorder: An Overview of Assessment and Treatment Approaches. Melrose S. Depress Res Treat. 2015; 2015: 178564. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4673349/
  • Vitamin D supplementation for treatment of seasonal affective symptoms in healthcare professionals. Frandsen TB1, Pareek M, Hansen JP, Nielsen CT. BMC research notes Published August 14, 2014. Volume 7, Issue ; Pages 528