Understanding SAD

As we head into the darker winter months of shorter days and less natural sunlight, some people can start to experience a particular type of depression disorder known as Seasonal Affective Disorder (SAD). This can also be known as ‘winter blues’ or ‘winter depression’.

Have you noticed that the winter months can influence your mood or feeling of self? Being aware of SAD is important for recognising symptoms when they arise and being able to seek appropriate help. Let’s take a look at the causes and different types of SAD, common symptoms and treatment options, as well as useful lifestyle changes you can make at home to feel better.

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‍What is SAD?

SAD is defined as a type of depression that reoccurs seasonally. For most people it comes on during the winter months and then goes away as we enter the spring months. The National Institute for Health and Care Excellence (NICE) currently recommends that SAD be treated the same as what we recognise as mainstream depression.  

Identifying the number of people that suffer with SAD can be tricky for a number of reasons, one of which is that SAD often goes unreported and undiagnosed. SAD can also accompany other conditions that mask or overlap with its symptoms, which can make it more difficult to diagnose.  

In the UK, some studies have reported that up to 6% of the population is affected by SAD on a yearly basis. By contrast, other studies report a lower, 2% prevalence of SAD across the UK population, but note that in addition to this, a further 20% of the population suffers from the ‘winter blues’, a milder version of SAD.  

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For most people, SAD comes on during the winter months

Causes of SAD

The exact cause of SAD remains largely unknown, however, there are a few possible explanations.

Where you live in the world

As SAD occurs primarily due to lack of natural sunlight during the winter, it appears to be more common among people who live either far north or south of the equator. This is typically due to decreased natural sunlight in the winter months.  

A lack of natural sunlight and our circadian rhythm

This is our bodies 24-hour internal clock, which is generally aligned to and responds accurately to changes in light and darkness. As each day gets shorter and we get less natural sunlight, our circadian rhythm becomes deregulated, most commonly delayed (though in a small minority can be advanced) with respect to the time of day and our normal sleep and wake cycles. Studies have shown that the more misaligned our circadian rhythm is with our sleep/wake cycle, the higher the severity of SAD symptoms observed.  

A drop in Serotonin and Melatonin levels

Serotonin is a brain chemical (neurotransmitter) which plays a part in regulating our mood. It there’s a drop in our serotonin levels, this may lead to experiencing SAD symptoms. This is a similar case with melatonin, a hormone that our brain produces in response to darkness and helps regulate our circadian rhythm.

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Symptoms and types of SAD

The symptoms of SAD are wide-ranging and somewhat atypical when compared to other depressive disorders. They can include:

Prolonged low mood  
Low energy and irritability  
Difficulty focusing  
Oversleeping
Overeating, craving carbohydrates, gaining weight, or a lack of appetite  
Loss of energy  
Withdrawal from social situations

SAD symptoms can often vary in intensity from one person to another. More mild or less intense symptoms can lead to the classification of ‘winter blues’ rather than a SAD diagnosis.

By contrast, some individuals can experience debilitating, severe symptoms, in which case the condition is simply referred to as SAD. In some cases, the symptoms of SAD can be as severe as other types of depression; even including thoughts of suicide.

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SAD Treatment

If you suspect that you might be suffering from the ‘winter blues’ or SAD, you should see your GP. They will be able to carry out an assessment and diagnosis, with recommendations for appropriate treatment if necessary.  

There are several treatment options, ranging from light therapy, to antidepressant medication, talk therapy and Vitamin D supplementation.

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Light therapy (SAD lamps) 

Light therapy can also be referred to as phototherapy or Bright Light Therapy (BTL). This represents a viable treatment option that may relieve symptoms of SAD but must always be monitored by a health professional.  

Light therapy consists of sitting in front of a SAD lamp daily (normally in the morning), which produces a powerful full spectrum of light that mimics natural sunlight. This works primarily by correcting the deregulation of our internal circadian rhythm. Light therapy is believed to improve SAD by suppressing the production of melatonin and increasing the production of serotonin.‍

Light therapy is safe for most people, and lightboxes that filter out harmful ultraviolet rays (UV) are available to affordably purchase. Those operating at 10,000 lux are believed to be optimal. Some adverse effects of light therapy may include eyestrain, headaches, irritability, and difficulty sleeping. They’re not recommended for people with eye conditions or damage that makes you sensitive to light, or if you’re taking any medication that increases photosensitivity (for example, St. John’s Wort, lithium, certain antibiotics).  

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Antidepressant medication

Antidepressants  are often considered as a viable option for treating SAD, though their effectiveness is not currently supported by a strong body of evidence.  

Selective serotonin reuptake inhibitors (SSRIs) are often the first choice of antidepressants for SAD, as they increase the level of serotonin in your brain, which can help lift your mood. Antidepressants are thought to be most effective if taken at the start of winter before symptoms appear and continued until spring.

Vitamin D supplementation

Many people with SAD or winter blues are found to have a deficiency of Vitamin D and supplementation is generally recommended to correct it. Vitamin D plays a crucial role in our bodies and regulates many important body systems and functions, including mood and immunity.  

Doctors generally assess our Vitamin D levels via blood tests, and recommend treatment based on the results. If you’re found to have a Vitamin D deficiency, supplementation will be recommended.

Talk therapy for SAD

Cognitive behavioural therapy (CBT) can be a useful treatment for SAD, as this form of talk therapy focuses on changing the way in which we interpret and act upon our thoughts. Counselling may also be a useful tool for dealing with SAD.

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What can I do at home?

If you’ve been diagnosed with SAD or the ‘winter blues’ it’s always a good idea to implement and stick to healthy lifestyle habits, which will complement other treatment options and have a positive influence on your symptoms and mood.  

Getting as much natural sunlight as possible during the winter is recommended. If you work indoors, it’s always a good idea to take a short walk outside during your lunch break. This will not only provide some much-needed natural sunlight, but you’ll also be getting some exercise, which has also been proven to boost mood.  

While working, try to position yourself next to a window if possible, and ensure that your environment is as bright as possible.  

In addition, managing stress, getting plenty of sleep and eating a balanced and healthy diet is also important.  

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