What is SAD and how common is it?

Many of us might feel happiest in the summer and a little fed up and lacking in motivation during winter. This is understandable as the weather is cold, there are fewer hours of sunlight, and the run up to Christmas can be stressful. However, for some of us the winter months can lead to a significant period of depression. This is relatively common with around one in 15 people feeling depressed between September and April, so-called ‘Seasonal Affective disorder’ (SAD).


What are the symptoms of SAD?

SAD is a cyclical mood difficulty where depressive symptoms are felt at the same time each year, most commonly in winter. This typically involves:

  • Wanting to withdraw from spending time with others
  • Feeling lethargic and lacking in motivation
  • Difficulties in sleeping
  • Eating more or less than usual
  • Feeling down or hopeless
  • Experiencing more negative and even suicidal thoughts

What can cause SAD?

Interestingly, SAD is more common among people who live in countries furthest from the equator. This could be due to less sunlight hours during the winter and longer days during the summer months. It makes intuitive sense that the change in season with less daylight hours leads to lower serotonin levels. Serotonin is a brain chemical that affects our mood, and the more we have the happier we feel. This can in turn affect levels of melatonin in the body, which impact on sleep patterns and mood.

In general, more antidepressants are prescribed during winter/Christmas. This could also be in part because our behaviour may change, with less time spent outdoors socialising and exercising, causing us to feel more lethargic and eat more ‘comfort food’. You might also be more likely to develop SAD if you have a family history of depression/SAD. SAD is also more likely to occur alongside an existing Major Depression or Bipolar Disorder.

How is SAD diagnosed?

A psychologist, psychiatrist or GP will be able to help you determine if you are experiencing SAD. It is important for you to record patterns you notice in your mood and energy levels across several months.

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What treatments are available?

1. Light therapy

Research shows that light therapy (sometimes called phototherapy) mimics natural outdoor light and can help to elevate brain chemicals. You can buy these bright light boxes/panels and use them in your own home, ideally within the first hour of waking each day. There are few known side effects and this can have a good effect quickly.

2. Psychological therapy

You can also access private psychological therapy with a clinical psychologist. Psychological therapy such as Acceptance & Commitment Therapy (ACT) or Cognitive Behavioural Therapy (CBT) can help to identify if SAD is an issue for you by recognising seasonal patterns and adapting to manage these feelings during the winter months.

3. Medication

Doctors may prescribe antidepressant medication for the winter months if depression is severe, to artificially elevate the amount of serotonin in the brain.

4. Focus on lifestyle

For any period of depression, ensure that you continue to eat healthily, exercise and socialise during the winter months. It can be helpful to think about how to adapt your eating and exercise patterns to the change of season, just as this happens in nature with plants and animals adapting. Remember that you are not on your own with experiencing these feelings and that these feelings will pass. Try not be hard on yourself and expect yourself to be doing the same things you would in the summer months, but acknowledge that it is helpful to keep up connections with other people and consider what brings you comfort (hot drinks and broths, wrapping up in warm winter clothes and getting some sunshine walking outdoors).

5. Mood supportive diet

While more research is needed for direct links between diet and SAD, we do know that nutrition status has a massive impact on one's mood. For this reason, it's worth being mindful of what you're eating during the darker winter months. Fill up on fresh, balanced meals with lots of mood supportive foods like lean protein, oily fish, green vegetables, berries, eggs, nuts and seeds, while being careful not to over consume sugar, processed foods and trans fats.

When should I speak to my doctor?

If you are considering light therapy or, if symptoms are severe, antidepressants speak to your GP. You can be referred or self-refer for support around depression in your local NHS Wellbeing Service, or seek out a private clinical psychologist.

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This article was reviewed on 27th October 2022 by Tracey Raye.

Dr Laura Keyes is a clinical psychologist, registered with the Health and Care Professions Council (HCPC) and British Psychological Society (BPS). She runs a private practice offering psychological therapy and assessments for neurodiversity to children and adults in Bedfordshire: drlaurakeyes.com


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