Winter is here and this might conjure thoughts of cosy nights by a fire, mulled wine, and the holiday season. However, it also brings colder days and longer nights and for some Seasonal Affective Disorder (SAD).

In this guest blog, Eilidh McNaughton outlines what SAD is, the causes, and provides some tips on how we can all look after our wellbeing this winter.

What is SAD?

SAD is a type of depression which has a seasonal pattern. In winter, it is more common in countries in northern latitudes. An estimated 22% of the UK population experience SAD. Of these, 20% experience ‘Winter Blues’ or subsyndromal SAD (s-SAD) and 2% experience SAD. Symptoms include low mood and energy, changes in sleep and appetite, and problems concentrating.

What causes SAD?

Current research into SAD indicates that our body clock (circadian rhythm) is altered by changes in the balance of neurotransmitters, hormones and vitamin D which could all play a role in the development of SAD.

Scientists think that the brain chemical Serotonin could play a role in SAD. There is a link between serotonin and mood, and research indicates that people with SAD have reduced serotonin activity. Research shows that this could be due to an increase of the serotonin transporter (SERT) in winter.

Figure: Serotonin is a brain chemical responsible for mood regulation. SERT is a serotonin transporter which deactivates serotonin. Evidence has shown that SERT is increased in those with SAD in the winter meaning serotonin activity is reduced which can cause SAD. Causes of this increase are unknown.

Melatonin, a hormone which is involved in sleep regulation, is secreted by a gland in the brain  (known as the pineal gland) in response to darkness. With shorter days and darker nights, winter can cause the gland to overproduce melatonin causing fatigue.

Research has shown that Vitamin D could play a role in depression and SAD, and this could be due to a link between vitamin D and serotonin. We get most of our vitamin D from sun exposure, so in winter levels decrease.

Although researchers have found that changes in circadian rhythms, serotonin, melatonin, and vitamin D are related to SAD, the precise causes are still to be discovered. 

What about summer SAD?

People can also experience SAD in the summer months. In fact, in countries nearer the equator like India, SAD is more common in summer. Symptoms are different from winter SAD and include anxiety, insomnia, and agitation. The causes of summer SAD are not fully known. Some attribute it to heat and humidity, changes to routine, and even high pollen counts.

How to treat SADness

Treatments to target the causes of SAD include anti-depressants and counselling, light therapy, and vitamin D supplements. If you think you may be experiencing symptoms of SAD, there are a few options available to try and if you are really concerned do talk to your doctor.

The treatment most associated with SAD is light therapy. A bright light is used daily to simulate sunlight, but evidence on its effectiveness is mixed. It can also have side effects including eye strain, headaches, and in some rarer cases hypomania or suicidal thoughts.  

In theory, Vitamin D supplements could improve symptoms of seasonal affective disorder but research to confirm this is still lacking and some have reported no benefits. However, at the recommended dosage these supplements usually cause no harm and could have other health benefits including for bone health and the immune system.

Tips for winter wellbeing

In this particularly challenging year, with COVID-19 restrictions in place and the threat of a ‘Digital Christmas’, looking after our mental wellbeing is more crucial than ever. We can all have good and bad days, so here are some tips for looking after yourself this winter:

• Stick to a routine
• Venture outdoors when you can
• Keep yourself occupied, e.g. take up a new hobby
• Reach out to family and friends (still following government guidelines and social distancing)
• Try mindfulness or meditation
• Seek help from a professional  

You can find further useful advice and help through the NHS and Mind websites.

About the author:

Eilidh McNaughton is a recent MSc Graduate in Science Communication and Public Engagement from University of Edinburgh. She is interested in mental wellbeing through personal experiences and is striving to beat the winter blues with dog walks and crochet.

We’re very grateful to Eilidh for writing this guest blog about SAD and sharing some really useful wellbeing tips. Look after yourself everyone, and each other.

Acknowledgement: Lead photo by freestocks.org from Pexels