Light Therapy for winter gloom
SAD is a subtype of a major depression. About 6% of North Americans are affected by SAD. And about 20% suffer minor symptoms. Typically the symptoms manifest at the end of autumn and disappear with the onset of spring. Sufferers of winter related SAD are more in numbers. The possible causes have not yet been realized but one evidence points towards the absence or decrease of sunlight causing a reduction in neuro transmitters. The eye sees the visible light of the sun which then proceeds through the retina increasing neuro motor activity. Visible exposure to light should be at least 2500 lux.
All forms of life react to sunlight and the lack of it affects all. Recent studies have proved horses to be suffering SAD. Horses when exposed to artificial light strips were less grumpy and were ready to be handled. But horses kept in darkness for long durations were into depression which manifested by their lack of hunger, excessive sleep and grumpy behavior. Exposing them to light led to a disappearance of these symptoms.
As seasonal affective disorder is related to sunlight and not temperature even people of higher latitudes are affected. 20% of the people in Sweden are affected giving weight to the theory that SAD is caused by lack of sunlight. Therefore a cure for SAD lies in exposure to light or sunlight.
Bright light box
Is the most effective of treatments and helps around 85% of the sufferers. A special light that provides 10000 lux which is much brighter than the office light is placed near the person. The light should not be stared into.
Duration of light therapy
Time duration for light therapy is decided by the doctor. But the time limit is either fixed from the beginning or the doctor gradually increases the duration. Normally doctors fix the duration to range between 30 to 60 minutes. Treatment continues till the onset of spring.
Fixed time for light therapy
Many doctors prefer the light therapy to take place during early dawn so that it mimics the light of the rising sun. A new theory advocates light therapy exactly 8 and a half hours after the production of melatonin and this works out to early dawn.
The daily light shower brightens the mood without medications. Simply sitting indoors under bright light does not relieve one of symptoms. The light box is necessary to relieve symptoms for it is specially designed to give light like the sunlight.
Success of light therapy relies on three factors:
- Intensity: light therapy should have the right intensity. Intensity is measured by the unit Lux which measures the amount of light received at a certain distance. Normally light should be around 2,500 to10, 000 lux.
- Duration: for light therapy ranges between 30 to 120 minutes.
- Timing: is important. People who use light therapy during the night complain of insomnia. This problem can be easily relieved by using the light during early dawn.
Side effects of light therapy are nil, the only known inconveniences are insomnia, eye pain and headache and these can be cured by changing the timing and duration of the light therapy.