Light Therapy (SAD) | Health Articles | Frequently Asked Questions about Seasonal Affective Disorder

What is SAD

Seasonal Affective Disorder (SAD) is now officially recognised as a medical condition thought to affect over 2 million of the British population. SAD is also known as the Winter Blues. About 10% of the population suffers to some degree with 2-3% suffering with clinical depression.

SAD can affect people of any age but most commonly it starts between the ages of 18-30. At one time it was thought that four times as many women as men suffered from SAD, but now increasingly men recognise the symptoms and seek treatment.

What are the symptoms

Typical symptoms include:

Depression, feelings of gloom and despondency for no apparent reason
Lethargy, lacking in energy, unable to carry out a normal routine
Anxiety, inability to cope
Social problems, irritability not wanting to see people
Sleep problems, finding it hard to stay awake during the day, but having disturbed nights
Loss of libido, not interested in sex or physical contact
Craving for carbohydrates and sweet foods, leading to weight gain. N.B. It has also been shown in studies that people with cravings for carbohydrates respond extremely well to light treatment

The Cause

SAD has a lot in common with the hibernation cycle of animals and research shows that this is triggered by a response to decreasing light levels. As the days grow shorter and the light becomes less intense, it increases the desire to 'hibernate'. Light intensity is measured in 'lux' the Latin word for light. On a summer's day in the UK we may have up to 16 hours of daylight at 100,000 lux. In winter an 8 hour dull day will give less than 5,000 lux and indoor lighting rarely exceeds 500 lux.

The Treatment

Historically, treatment for depression involved the use of drugs, however, in recent years, research in the USA and UK showed that SAD sufferers responded, often quite dramatically, to Bright Light Treatment. Researchers believe that the lack of light causes an increase in the production of Melatonin (the hormone that makes us sleepy at night), and a reduction of Serotonin, the lack of which causes depression. The exposure to bright light therapy reverses the process, with the additional benefit of being drug free. By providing summertime levels of light during the winter you can successfully alleviate the symptoms of SAD with the result that former sufferers can lead a normal, happier life and beat the Winter Blues.

How Do I Know if I've Got SAD

If you get the symptoms recurring for two to three years at about the same time every autumn/winter then this would point to the probability that you suffer from SAD. If you have any question about light therapy then it is best to talk the treatment over with your physician before starting to use a light box. This is especially relevant if you are currently taking any medication.

How Does the Light Therapy Work

The light has to go in through the eye and it travels down to the pineal gland deep in the brain. It rebalances the melatonin (the hormone that makes you sleepy) and the serotonin (the hormone that makes you feel good). At the most basic level it fools the brain into thinking its still summer! Light is now recommended as the treatment of choice for seasonal affective disorder.

Can I Use a Light Bulb

No, you simply don't get the intensity of light that you need with a light bulb. A light bulb gives only 300 – 350 lux. Recent studies by Dr Norman Rosenthal and others have shown that what you need to treat SAD is a minimum of 2,500 lux (Lux is a measurement of the intensity of the light.)

Do I Have to Stare at the Light Box

No, you can carry on with your normal routine with the light box on beside you. If you are working it can be beside your computer terminal or on your desk, or if you are at home you could use it while watching TV, ironing or working in the kitchen. It must fit in with your routine to ensure that you use it for the amount of time that is necessary for you. Ideally it should be about an arms distance away from you, within your peripheral vision, not directly in front of you. When choosing a light box the basic factors for consideration are, intensity (10,000 lux at what distance), duration of treatment time, and the best time for you to take the therapy.

How Long Does it Take to Work

This can vary as everyone is an individual. You can usually see the difference within 7 to 10 days, with some people it can be as little as 4 days, but others will take 2-3 weeks. The rule of thumb is that if it takes 7 days for the treatment to be affective then symptoms will recur within 7 days if treatment is stopped.

Who Can Benefit From Light Therapy

They are designed specifically for treatment of winter depression, but people with other forms of depression can be lifted with the light therapy. With Manic Depressives it should not be used during the Manic phase. Sufferers of MS and ME can also benefit as some of the symptoms can replicate those of SAD.

Do They Work

Yes! Research has shown that they are effective with response rates of up to 90%.