More about light therapy for SAD
What is light Therapy?
This treatment consists of sitting in front of a special bright light for a session each day. Light intensity is measured in lux. Ordinary light bulbs are not strong enough as they only give out 200-500 lux. To treat SAD you need a light source of at least 2500 lux (about 10 times that of ordinary light bulbs).
What does treatment entail?
Special light boxes are made for the purpose of treating SAD. Follow the instructions that come with the box. Basically:
- You start treatment in the autumn, as soon as symptoms begin.
- You sit 2-3 feet away from the light box.
- You face the bright light, but you do not have to look directly into it.
- The length of light therapy needed each day varies. If the light source is very powerful (10,000 lux) then 30-45 minutes per day is usually sufficient. With less powerful light boxes, 2-3 hours a day are needed.
- You can do things such as eating, reading, knitting, etc, whilst sitting in front of the light box. Some people with 'desk jobs' are able to get on with their work with a light box in front of them.
- Some studies suggest that treatment in the morning works best, but other studies do not confirm this. So, the best time to do it is the time most convenient to yourself. However, evening sessions cause difficulty with sleeping afterwards in some people.
- Some people have their light therapy session whilst having their breakfast and reading the morning paper, or get up a early to have a session before going to work.
How does light therapy work?
The logic is that it 'replaces' the bright sunlight which you normally see in the summer. But, it is not clear exactly how it works. It is not simply extending the length of the daylight hours. In fact, you usually do light therapy sessions at some stage in the daytime, not when it is dark. Bright light affects the retina (back of the eye) which sends nerve signals to parts of the brain. This is thought to affect the level of certain chemicals and hormones which you make in parts of the brain which affect mood.
How quickly does it work?
Most people notice an improvement in symptoms within 3-4 days. Symptoms will stay improved so long as you keep on with treatment every day until spring. In some cases it takes up to 4-6 weeks of treatment for symptoms to improve. It does not work in every case. See your doctor for other treatment options if you do not notice an improvement after 6 weeks.
Is light therapy safe?
It appears to be safe. There is a theoretical risk of damaging the retina (back of the eye). However, there have been no reports of harm with the specially designed light boxes. The light boxes used to treat SAD do not emit much ultraviolet (UV) light which is the main damaging part of sunlight to the skin and eyes. Side-effects occur in some people and include: headaches, difficulty sleeping after an evening session of light therapy, irritability and tiredness.
Note: you should not use sun tan machines as a source of bright light. The light from sun-tan machines gives off a lot of ultraviolet (UV) rays, which can harm your eyes. It is best to use only the light boxes which are made especially to treat SAD.
What about natural sunlight?
Natural sunlight, even on an overcast day in winter, provides more 'lux' than the artificial light source in a light box. So, going for a walk outside every day for 1-2 hours during the daytime may ease symptoms. However, this may not be a realistic option for many people. For example, if you work indoors.
How can I get a light box?
You cannot get a light box on prescription from the NHS. Various companies make them and they cost from about £100. The SAD association (see below) provide a list of suppliers. Some companies will allow you to 'try before you buy' to see if it works for you before you commit to buying a light box.
Does light therapy work for other types of depression?
No. It only works if you have SAD.
Further help and information
SAD Association (Seasonal Affective Disorder Association)
PO Box 989, Steyning, West Sussex, BN44 3HG
Tel: 01903 814942
Web: www.sada.org.uk.
A voluntary organisation which informs the public and health professions about SAD and supports and advises sufferers of the illness. It produces a newsletter thrice-yearly, and other publications, has a network of contacts, a lightbox hire scheme, and raises money for research into SAD.
© EMIS and PIP 2004 Updated: May 2003 CHIQ Accredited
More help and advice
- Ten ways to fight depression
- How sun can help SAD
- Read in-depth information on depression
- Tips on coping with depression
- How a lightbox changed Nikki's life
- Have you suffered from SAD? Share your experiences
Average rating:
