Seasonal Affective Disorder (SAD) is a type of depression that’s related to the change of season.

It is estimated it affects 1 in 15 people between September and April in Ireland. 

I suffered from SAD for many years when I moved to Ireland. Once diagnosed, there are some pretty clear actions you can take and it is a quite an established “condition” in the northern hemisphere. 

What are the symptoms?

  • Sleep problems
  • Lethargy
  • Depression, feeling sad and low moods
  • Mood Changes
  • Loss of interest and libido

What cause SAD? 

Although the exact cause of SAD remains unknown, most agree that some of the factors that come into play are the lack of daylight, which result in changes in the circadian system, drop in serotonin and melatonin levels, 2 key hormones which affect both your sleep and your mood. 

The Baker Heart Research Institute in Melbourne states that, based on its research , one reason of feeling the blue in winter is the change levels of serotonin in our brain, which is directly related to the amount of daylight we are exposed to. 

SAD affect more people far from the equator and women, and is more frequent between the age of 18-30 years old. 

What can you do? 

SAD is a pretty established winter mental illness in the northern countries who experience much shorter days in the winter. SAD is mainly related to the lack of daylight. There are some clear actions you can take listed below (non-exhaustive): 

Vitamin D

Vitamin D comes from food but also from daylight so it is easy to see the link with winter deficiencies. Vitamin D is essential for your bones and some important body functions, but there is also growing evidence of the effect of Vitamin D deficiencies on depression. I take Vitamin D all year long, but higher doses in the winter. I definitely find it affects my mood in the winter.  

Vitamin D deficiency has now been linked to breast cancercolon cancerprostate cancerheart diseasedepressionweight gain, and other maladies


Test your Vitamin D levels and ask a practitioner (GP, nutrisionist) for the dosage as excess of Vitamin D can have side effect.


Outdoor if you can – exercise improve your moods and has proven benefits on the activity in your brain. I exercise, 3x a week, for short sessions, and I notice the difference when I don’t for any reasons for a week, it makes a difference and specially in the winter, this is a non-negotiable!

When exercising, our brain releases an hormone called endorphins which creates a feeling of “comptent or happiness “ 

Get some more light

Go out for a walk at lunch time. We don’t need enough daylight anyway in general, but specially in the winter. Today the average westerner spends 90% of their time inside. If you seat in an office, beside a window, you get 10x less light (measured in LUX) than being outside.  A 20min walk outside will provide you way more light.

Light therapy

You can buy those special SAD lights, they are inexpensive, and depending on the output, all you need is 30min-1h every morning. It is important to use them only in the morning as otherwise they might affect your sleep. I had one for a while and it brings some peace of mind to know that you are getting the light exposure that you need for sure, without worrying about getting out to get some direct light. Get a good one though!  


SAD for me was essentially about beating the Low Moods, and this book from Patrick Holdford was really useful. As you can read, there are a lot of natural approach to low mood/depression.