How Effective is Light Therapy for Depression?

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  • Written By: Drue Tibbits
  • Edited By: Angela B.
  • Last Modified Date: 05 October 2019
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Light therapy is very effective in treating depression if the depression is related to seasonal affective disorder (SAD). Most people experiencing this type of depression will find relief with light therapy. It is the preferred treatment for SAD, because it is well tolerated, does not require a prescription and is easily accessible. Although light therapy for depression is as effective as medication in the treatment of SAD, there are no conclusive studies showing that light therapy works with other forms of depression.

For some people, lower seasonal light levels can result in SAD. The shorter days of fall and winter can disrupt the body’s natural circadian rhythm, the body’s 24-hour clock that regulates sleeping and waking. The disruption of the circadian rhythm can cause sleep disturbances and depression. Light therapy for depression helps the body regain its natural circadian rhythm, allowing for normal sleep patterns and eliminating depression. Other forms of depression, such as clinical depression, pre-menstrual syndrome and bipolar disorder are not caused by disruptions in the circadian rhythm and seem to be unaffected by light therapy.

Light therapy for depression involves the use of specific forms of bright light. Light intensity is measured by lux, with bright sunlight measuring 10,000 lux. Tanning beds and household lights do not emit high enough lux or the correct type of light and are not effective.


Portable light boxes, made for light therapy, can reach 5,000 lux and provide the best intensity of light for therapeutic purposes. “Cool white” fluorescent lights produce less ultraviolet radiation than full-spectrum lights and, although they produce less lux, can be useful in light therapy. Exposure to 30 minutes of 10,000 lux is equal to an hour exposure of 5,000 lux.

A majority of people with SAD find that light therapy for depression is most effective when used during morning hours, though it sometimes works better during the afternoon or early evening. Each person’s natural circadian rhythm is different, so the amount of lux needed and the time exposed needs to be tailored to the specific person to achieve results. In most people, elimination of SAD-related depression can occur within a few days of beginning to use light therapy, although some people may not see relief for three weeks or more. In all SAD sufferers, the depression returns when light therapy is discontinued. Everyone responds differently to the amount of lux and to the time exposed to light, so the use of light therapy for depression should be monitored by a physician.


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Post 2

Many people surfer from seasonal affective disorder and have no idea how the condition is affecting them. One of the things you should be on the look out for is a change in appetite. It is common knowledge that some people use food to suppress their emotions.

With SAD, you may find that you crave more sweets or starchy foods. And of course, these foods are most likely going to lead to another frequent symptom of SAD--weight gain. So those extra pounds you put on during the winter and then work so hard to lose before the warm weather arrives could be related to seasonal depression.

Sad can also interfere with your sleep patterns and this can lead to a long list of problems including difficulty concentrating, fatigue, mood swings and a loss of interest in daily activities.

Post 1

I have a friend who lives on Cape Cod, Massachusetts. Anyone who has ever been there knows that the place is great for spending the summer days and enjoying all that the towns on the cape have to offer. There is water all around. Plenty of vacationers and night spots. The restaurants are good and all of these things make this an exciting spot during the summer season.

On the flip side, Cape Cod is not so inviting during the winter. The days are short and often cloudy and dreary, and I won't mention the snow, which can be seemingly endless some winters. This is when my friend has trouble with his chosen home.

He suffers from SAD

and at least a couple times during the winter he has to escape to somewhere warm and sunny. He usually goes to Florida. He gets depressed once the cold weather sets in and continues to get worse until the warm weather and sunshine return. The trips to Florida allow him to keep functioning during the winter.

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