Seasonal Affective Disorder Light Therapy
Light therapy for SAD
I do get quite depressed during the dark winter months. Medication helps but I don’t want to take it every year. What else can I do?
The newer antidepressant drugs (SSRIs) have been found to be effective for SAD, whereas the older tricyclic antidepressants (TCAs) might make people even sleepier. Our environments change during the winter in various ways that may affect us; for example, we may have fewer opportunities for enjoyable sport or hobbies, our jobs may become more difficult, and Christmas can be stressful.
There is now fair evidence that light treatment is as effective as antidepressant medication for some people. The Swiss health service now provides it as a treatment. The American Sleep Disorders Association also recommends its application for disturbed sleep rhythms among shift workers, or from jet lag, Alzheimer’s and ageing.
Seasonal factors may affect people with various types of depression, and some experts suggest everybody with depression should at least try light treatment as well as their usual treatment.
What exactly is light therapy?
Light stimulates our nervous systems, and alters our circadian rhythms (body clocks). The average office has a light intensity of about 500 lux. In contrast, a bright summer’s day has about 100,000 lux. Lightboxes are available commercially that produce about 10,000 lux and cost from £100 to £300.
The published research has been done with this sort of equipment. You need to sit about an arm’s length from it for 30-90 minutes daily, depending on the size of the lightbox. That’s quite a long time!
Users treat themselves through the winter months. So far, only a few psychiatric units provide this treatment. You can also replace domestic lightbulbs and strip lights with ‘full spectrum’ lighting, which simulates natural daylight, but it would be difficult to light a whole room to 10,000 lux comfortably.
Are there any side-effects?
Yes. Some people get headaches, eye strain, restlessness, and even insomnia. It is best used earlier in the day if this happens. You should take advice about it if you have eye disease. Too much light treatment may cause mild hypomania in people with a tendency to bipolar illness.
