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SAD lamps and seasonal affective disorder

Seasonal Affective Disorder: Symptoms and Treatments

By Joanna Pearl

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Seasonal Affective Disorder: Symptoms and Treatments

We explain the signs and symptoms of seasonal affective disorder and what you can do to treat it – from self-help to SAD lamps.

Seasonal affective disorder (SAD) is a severe depression experienced during the winter months (commonly autumn and winter, ending in spring). It usually begins between the ages of 20 and 30, but can develop at any age. Three quarters of those affected are women.

SAD is diagnosed if you have had periods of depression that have occurred during the winter months for at least two years running, and if you have symptoms that are not typical of depression, such as increased sleepiness and craving sweet foods. 

If your symptoms are so bad that they are having a negative effect on living a normal life, see your GP for medical help, as it’s important to treat SAD symptoms as depression.

Many more people suffer from the 'winter blues' rather than SAD. The winter blues is a less severe form of the condition and a normal response to gloomy winter days.

Light therapy is a popular self-help treatment – find out more about SAD lights using our SAD lamp reviews.

What are the symptoms of SAD?

SAD, which can start when the clocks go back in October, leads to symptoms such as low mood, low self-esteem and confidence, a loss of pleasure in usual activities, marked lethargy, feelings of guilt and social withdrawal. It may even lead to suicidal thoughts. 

Unlike sufferers from non-seasonal depression, people with SAD will tend to sleep more rather than suffering from disturbed sleep.

Also unlike typical depression, SAD-sufferers may also crave carbohydrate-rich and sweet foods, which can lead to an increase in weight.

See NHS Choices for more about SAD and symptoms.

What causes SAD?

There is no simple answer to what causes seasonal affective disorder, but it is thought that SAD may be related to the lack of light in winter and high levels of the hormone melatonin, which is produced within the brain when it is dark. Melatonin tells our bodies it's night and therefore time to sleep.

However, medicines that stop the secretion of melatonin don't stop SAD, so this is clearly not the only factor in play.

People with SAD are also thought to have a lower-than-normal level of the chemical serotonin.

What are the treatments for seasonal affective disorder?


The Royal College of Psychiatrists says that self-help will usually be enough to ease mild SAD, and even help those with a severe form of the condition.

Self-help tactics include going outside as much as possible during the winter to see more natural daylight, and keeping up any regular exercise, ideally outdoors.  

So, for example, if you work in an office, you might try to take a daily walk in the park at lunchtime. A walk could give you 3,000-4,000lx of light even on a cloudy day, and over 10,000lx (the level SAD lights generally emit) on a sunny summer morning. Even standing or sitting nearer windows will enable increase exposure to more natural daylight.

You could also use and switch on more lamps indoors, and have extra ceiling lights put in.

A winter holiday in the sun may help but, unfortunately, the benefits will last only for as long as you are away.

Light therapy 

Light therapy is a recognised therapy that focuses on replacing the sunshine you would see in summer. 

SAD lamps – sometimes called SAD lights or light boxes – are a form of light therapy, a treatment for SAD or regularly occurring episodes of depression during specific times of year, usually winter.

Find out more about how to choose an SAD lamp.

Other options

Alternatives include anti-depressants, which may be helpful in severe cases of SAD, particularly if taken before symptoms emerge.

Talking therapies such as cognitive behavioural therapy (CBT), counselling or psychotherapy may help you cope with symptoms. Contact your GP for further information.