Suffering with the winter blues
Friday 2 February 2018

A lack of daylight in the winter months can cause Seasonal Affective Disorder (SAD), a condition characterised by low mood or depression in the darker, shorter days. Although easily dismissed as a myth, it is a recognised mental health disorder which can have a serious impact on sufferers.

Although many people are affected to some extent by seasonal change, and prefer longer, sunnier days, for those experiencing SAD, the impact can be much greater – affecting energy levels and mood, which in some cases can lead to, or exacerbate, symptoms of depression.

Symptoms of SAD can range from a lack of energy and sleep problems, to anxiety and panic attacks, to overeating or increased use of drugs or alcohol.

Lack of light

The scientific view is that SAD is related to how the body responds to daylight. The mental health charity MIND explains one of the theories: “When light hits the back of the eye, messages are passed to the part of the brain that controls sleep, appetite, sex drive, temperature, mood and activity. If there’s not enough light, these functions are likely to slow down and gradually stop. Some people seem to need a lot more light than others for their body to function normally.”

Other causes

Other causes of SAD are thought to be low levels of the mood-regulating hormone serotonin, and too-high levels of the sleep hormone, melatonin. External triggers can also cause the onset of SAD, such as a major or traumatic life event, physical illness, a change of diet or medication, and use of (or withdrawal from) drugs and alcohol.

MIND also notes that people who have moved to the northern hemisphere after living near the equator are particularly at risk of developing SAD.


As SAD is a recognised mental health disorder, the National Institute for Health and Care Excellence (NICE) recommends that it should be treated in the same way as other depressive illness.

This includes using talking therapies such as counselling or cognitive behavioural therapy, and/or medication such as antidepressants. The NHS and MIND also recommend: getting as much natural light as possible, sitting near windows when inside, exercising regularly – outside if possible, eating a healthy, balanced diet, and trying to avoid stressful situations.

Some evidence has found that light therapy can improve the mood of SAD sufferers considerably. The therapy involves sitting by a light box, usually for around 30 minutes to an hour each morning.

While light therapy is a popular treatment for SAD, NICE advises that it is not clear whether it is an effective remedy, but some studies have concluded it is, particularly if used first thing in the morning. It is important to check that the light box is medically approved for the treatment of SAD and is produced by a fully certified manufacturer.

MIND also notes that St John’s wort is a popular herbal remedy that some find helpful for mild or moderate symptoms of SAD. However, the charity warns that: “It may not be suitable for severe SAD or if you use a light box because it can make your skin very sensitive to light.” St John’s wort should not be taken alongside prescription antidepressants, and people should consult their GPs before using it with any other medication.

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