Seasonal Affective Disorder (SAD) is often treated by light therapy (or phototherapy) which exposes the person to bright light for a certain period of time, depending on the person’s symptoms. According to the National Organization for Seasonal Affective Disorder (NOSAD), light therapy has been proven effective in over 80 percent of diagnosed cases.

Light therapy is administered through a light box containing white fluorescent lights on a metal reflector and shielded with a plastic screen. These boxes block the dangerous ultraviolet rays to protect the user. The patient sits in front of the box with his or her eyes open, but not looking directly into the light, which means he or she can go about everyday tasks (such as studying, watching television, eating, etc) while being treated.

Light exposure generally ranges anywhere from 10 minutes to several hours per day, depending on the severity of symptoms. NOSAD reports that average home or office lighting delivers an intensity of 200-500 lux (a measurement of light intensity in photometry); the minimum dose necessary to treat SAD is 2,500 lux. Some light boxes deliver as much as 10,000, which can significantly shorten treatment time.

For mild symptoms, the National Mental Health Association (NMHA) recommends spending time outdoors during daylight or making sure your home or workspace receives as much sunlight as possible. Any daily exposure to sunlight you can get will be beneficial to your treatment.

Getting the Most Out of Light Therapy

Because not everyone has the same biological clock, light therapy treatment will differ among patients. SeasonalAffectiveDisorder.com offers these general tips – for all patients – to make sure you reap the full benefits of light therapy and are on the road to feeling better:

• Start Preventatively: Before you even begin to develop depressive symptoms, make a constant effort to expose yourself to natural light as often as possible. If you are just starting off with light therapy, early maintenance may mean you won’t have to increase your time from 15 to 20 minutes each day.
• Taper Off: When the season ends, don’t stop spontaneously. Most people make this mistake and think they are ready to stop treatment, but then end up rebounding quickly. It’s best to cut about five minutes off each week before you quit.
• Consistency: Try your best to keep a consistent sleep/wake routing and use your light box on a regular basis – this will help you avoid any dips along the way.
• Adopt a Circadian Lifestyle: Pay close attention to your biological clock. Don’t try to fight sleep or try to sleep when you are energized.
• Combination Therapy: If light therapy doesn’t seem to be enough, consult with your doctor or practitioner to see what other treatment options are available.

When your goal is to reset or regulate your biological clock, light therapy is most effective when your internal clock is looking for light signals. This is often in the morning right after you awaken, and again in the late evening and night. If you find you become too energetic, euphoric, nervous, jittery, or start waking up earlier than desired, you may need to reduce the amount of light or the change time of day you are using the light box.

Side Effects of Light Therapy

Light therapy, when used as directed, has been proven to be very safe and effective with no long term side effects or damage to the eyes. However, some people experience negative reactions to light therapy. The side effects are rare and almost always treatable. Here are a few of the most common:

• Nausea;
• Headache;
• Eyestrain;
• Irritability;
• Anxiety or nervousness.

Side effects are often triggered by too much light, so, unless directed by a doctor or practitioner to use more exposure, you should limit yourself to no more than one hour. Another way these side effects can be triggered is when a person’s eyes are not used to bright light and need to be acclimated to the light.

If you experience any of these side effects, it is recommended that you stop the light therapy for a day and then slowly acclimate yourself to the light with five-minute intervals each day for the first few days and gradually add two-to-five minutes each day thereafter.

Sources: National Mental Health Association; National Organization for Seasonal Affective Disorder; SeasonalAffectiveDisorder.com