The Winter Blues: Seasonal Affective Disorder

18 October 2023 at 09:41 · 5 min read

A man walking in the snow under a red highlight

There can be many reasons or triggers for depression, but one of the least often discussed could be as simple as the natural changing of the seasons.

Seasonal Affective Disorder (SAD) is a form of depression that is believed to occur on a yearly basis, usually through the winter months - hence it is often called ‘Winter Depression’.

Like other forms of depression, those experiencing SAD usually report some combination of the following symptoms:

  • Persistently low mood
  • Decrease in energy and a loss of interest in hobbies and activities
  • A loss of pleasure or interest in normal everyday activities
  • Noticeable weight gain or loss and changes in appetite
  • Changes to sleep patterns or difficulty sleeping
  • Increased irritability

Whilst it’s tempting to write off some of these things as simply a case of ‘Winter Blues’ it’s worth taking the symptoms and the condition seriously. 



The exact causes of SAD are still not totally agreed upon and the mechanism by which it operates is also not yet fully understood. The most likely culprit would seem to be the decreased amount of sunlight in winter months which can cause a reduction in vitamin D production.

There are biological factors potentially at play. Sunlight is needed for our internal ‘body-clock’ (also known as our circadian rhythm) to function optimally. A significant - albeit gradual - decrease in the amount of sunlight we receive may disrupt this rhythm enough to trigger SAD in some people. 

In addition, SAD often seems to be associated with a higher production of melatonin in the body. This in turn is associated with people feeling more tired and sleepy, contributing further to symptoms. By the same token, it is thought that serotonin levels - which are believed to affect mood - can decrease at the same time, further increasing depressive symptoms.

Finally, there also seems to be an element of genetics at play, with greater dispositions to SAD being transferred from parents to children. 


So, short of jetting off to a sunny beach, what can be done to help deal with SAD

Often, doctors recommend lifestyle changes to help ameliorate SAD. Some of these are typical for other forms of depression or mental conditions and include things like regular exercise, a healthy diet and a mindfulness of general stress levels. 

But some measures also include altering daily routines to make the most of the available sunlight. This might be something as simple as altering one’s work schedule and waking up earlier or later in order to get as much sun exposure as possible during one’s daily commute. 

Perhaps one of the more interesting treatment options is light therapy - i.e. using devices to try and replicate the effect of higher levels of sunlight on the body. The evidence for the efficacy for this has been unclear and the method has often been labelled as a gimmick.  

Seeking therapy with a trained and qualified psychologist has though found to be the preferred treatment for SAD. As with many conditions, it can vary greatly from person to person. In some cases, medication, in addition to therapy, has been found to have the best result.


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