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Seasonal Affected Disorder (SAD)

What is it?

Seasonal affective disorder is a condition whereby a person develops symptoms of ‘depression’ during the winter months. In the UK this can occur from September to April, with the worst times generally between December and February.

What are the symptoms?

Seasonal Affected Disorder
The symptoms of SAD are varied and can be distinguished from the usual feelings of feeling ‘gloomy’ or ‘down’ during winter by the fact that the symptoms of SAD are usually more pronounced and may affect everyday tasks. Feeling ‘blue’ or ‘down’ during the cold and dark months winter can take its toll on everyone, but SAD suffers generally find it much harder to cope and serious suffers usually have at least 2-3 of the symptoms listed below.

  • Feelings of sadness or low mood.
  • Feeling weepy
  • Disturbed sleep pattern – for instance difficulty getting to sleep, waking up during the night and unable to go back to sleep.
  • Sleeping excessively
  • Change in appetite – for instance not feeling hungry or eating much more than normal
  • Tiredness and fatigue with a loss of energy
  • Feelings of anxiety
  • Prone to illness
  • Poor concentration
    Agitation or slowing of movements.
  • Feelings of worthlessness, or excessive or inappropriate guilt.
  • Recurrent thoughts of death and suicide

For some people, the symptoms of SAD are debilitating and they can’t function at all. However many people with SAD may have a few of the symptoms above and may carry on at a sub-optimal level throughout the winter.  In most people the symptoms will improve during the spring fairly quickly. In some people this may result in big burst of energy and in others even mania (abnormally high moods) which can be equally difficult to manage.

If you feel you may be suffering from SAD – see your GP.


Researchers are still not completely sure what the ‘exact’ cause of SAD. It is believed that when light touches the back of the eye (the retina) it stimulates nerves to send messages to a part of the brain called the hypothalamus. This area is thought to regulate sleep, appetite, sex drive, temperature, mood and activity Sunlight also regulates the release of chemicals called serotonin and hormones such as melatonin. A lack of serotonin can lead to depression, whilst melatonin can cause sleepiness and is generally released during darkness.

In the winter months, when the days are shorter and the light intensity is reduced, there is less stimulation of these parts of the brain and consequently possibly lower levels of serotonin and higher levels of melatonin leading to the symptoms of SAD.

How common is it?

Anyone can suffer from SAD.  However in general it affects four times as many women as men. Symptoms usually begin between 18-30 years of age.  SAD predominantly affects people who live in the northern and southern hemispheres since these countries are the ones that have the highest number of darkness hours during the winter months. Countries closer to the equator have very little variation in the number of hours of daylight throughout the seasons.

It is believed that SAD affects around 10 per cent of the population in Northern Europe (that’s 1 in 10 people), and 2 per cent experience severe symptoms. People who have moved to SAD affected countries (i.e. areas with significantly less sunlight during the winter months), from the tropics, may be more likely to suffer from SAD. SAD can also affect people who work long hours in places with no access to sunlight (for instance office blocks or basements) and these people may suffer from SAD all year round.

It is also possible that SAD is a hereditary disorder and about 1 in 7 first-degree relatives (mother, father, child, brother, sister) of people with SAD are also affected.

How is it treated?

There are three main ’treatments’ for SAD. Bear in mind, these will treat the symptoms but will not provide a ‘cure’ of the condition and will need to be continued throughout the darker months.
  • Improving access to natural light
  • Light therapy
  • Treatments for depression

Natural light

Whatever the exact cause of SAD – the main causative factor is the lack of natural light. Although during the winter months the sun is not as bright as it normally is – it is well worth making the most of the natural light – especially during the midday (when the sun is at its brightest) when the opportunity arises. This may include going out for a walk, sitting in a conservatory or in the garden (weather permitting!). Although this may not manage your symptoms completely, it may help.

Another more costly suggestion is to get some winter sun. This may help to improve symptoms whilst you are exposed to brighter light levels and may also help to break up the monotony of winter.

Light therapy.

Numerous studies have shown that light therapy can help to alleviate symptoms of SAD. For all purposes ‘light therapy’ is simulates the natural light produced by the sun as realistically as possible. The idea is then to expose yourself to a certain amount of this ‘natural’ light per day, usually in the morning. It is important to remember that light therapy – is not the same as sitting under a regular bright light. Normal light bulbs only give out about 200-500 lux (lux is the way light intensity is measured), whereas light boxes will usually give out at least 2500 lux (about 10 times that of ordinary light bulbs).

Light boxes are generally designed in such way as to allow you to carry on with normal activities as you get ‘treated’ such as working, reading or even eating. Treatment periods are usually about 30 minutes per day and should be started before symptoms begin if possible. Patients have reported an improvement of symptoms within days, but it may take up to six weeks for a significant improvement.  

Lately there has been some controversy about whether increasing the amount of light to the ears may also help alleviate symptoms of SAD but this is yet to be proven.

Unfortunately light boxes are not available on the NHS, but some manufacturers may be able to offer you a free trial.

Treatments of depression

Sometimes the best way to manage SAD is to use similar treatments as those used for depression. There are a number of treatments for depression – beyond the scope of this topic. You should always see your GP if you think you are depressed and they will point you in the direction of the best treatment for yourself.
These may include:

  • Anti-depressants
  • Cognitive behaviour therapy (CBT)
  • Counselling or therapy


Top tips for managing SAD:

  • Avoid stress – having SAD can make it difficult to manage some everyday tasks. Plan ahead so you are not stressed out during the winter. Make sure you have a light box (if this helps) so you can start your treatment as soon as your symptoms begin and leave stressful tasks (e.g. moving house, job,  buying your xmas presents etc.) during the summer months when you are productive
  • Eat healthily with regular exercise – although many people with SAD crave carbohydrates, its important to also eat plenty of fruit and vegetables. Regular exercise can also help keep stress and anxiety levels down.
  • Take regular walks or sit in places exposed to natural light
  •  Join a support group or online forum – sharing your experiences and tips can go a long way to stopping you from feeling isolated.
  • Try to ‘get away’ to somewhere with lots of light – this can bring temporary relief of symptoms of SAD and may also help to break up the monotony of the winter.