Light Therapy

light therapy

By Tammy Preston, MS

Light therapy is now an accepted treatment for a number of illnesses, including SAD (Seasonal Affective Disorder), sleep disorders and even acne and psoriasis. This simple therapy has also been recently investigated as a possible treatment for adult ADHD, and has shown promising results.

What Is Light Therapy?
Light therapy (also known as phototherapy) consists of exposure to daylight or to specific wavelengths of very bright, artificially produced light, for a prescribed amount of time, sometimes at a specific time of day.

How Does Light Relate to Adult ADHD?
Light and day-length has been shown to impact mood disorders such as depression as well as sleep/wake cycles (aka circadian rhythm). Because adults with ADHD often struggle with both depression and sleep disorders, researchers became interested in examining the effect of light on these and other ADHD symptoms.

A study led by Dr. Yuri Rybak of University of Western Ontario, and Dr. Robert Levitan, a clinical researcher at CAMH, was the first to investigate the effectiveness of morning bright light therapy on the delayed sleep/activity rhythm and symptoms of depression often experienced by adults with ADHD.

Does Light Therapy Help Reduce Adult ADHD Symptoms?
In Rybak and Levitan’s study, participants were exposed to thirty minutes of light therapy, using a full-spectrum fluorescent light box that filtered out ultraviolet wavelengths.

The treatment was demonstrated to markedly reduce several key adult ADHD symptoms. More than half of the of the study subjects experienced fewer symptoms of depression after light therapy, and nearly a third showed a reduction in adult ADHD symptoms, such as inattention, difficulty following through, impulsivity and fatigue.

Although the researchers suspected that light therapy would impact ADHD symptoms, they were surprised to find that the strongest predictor of a reduction in ADHD symptoms was a change in circadian rhythm rather than a decrease in signs of depression. The investigators speculate that light therapy may impact a basic arousal mechanism in adults with ADHD, as well as reset circadian rhythms. But additional research will be needed to completely understand how light therapy works to influence adult ADHD.

Sign Me Up! How Do I Use Light Therapy?
To use light therapy, you sit in front of a specially designed light box with your eyes open. The light box emits a high intensity spectrum of light that you can’t get through normal household lighting (So trying to save a few bucks by sitting close to your desk lamp won’t cut it). The special light used in light therapy mimics exposure to outdoor light and causes biochemical change in your brain that can lift your mood and reset your internal clock.

The subjects in Rybeck and Levitan’s study sat in front of their light box for 30 minutes. However, you should not begin light therapy without discussing this treatment option first with your physician or psychiatrist. A professional can best determine if this type of therapy is right for you. They can also advise you on the best type of light to use, optimal length of expose, the distance you should be from the light and the best time of day for your treatments.

Choosing a Light Box
Don’t try to save money by making your own light box. Some people try to make their own – and that’s a bad idea. Professional light boxes are made to mimic light that comes from the sun and have filters in place to filter out ultraviolet light that can damage your skin and eyes. You may not get the full benefits if you make your own and you could end up damaging your skin and eyes.

A better option? Choose a professionally made light box that filters out most damaging ultraviolet rays. There are also light boxes used to treat skin conditions like psoriasis and eczema that don’t filter out these rays. If you buy one of these boxes, you’ll end up exposing your skin and eyes to damaging ultraviolet light.

Consider the Intensity of the Light
Light intensity matters. Look for a box that emits an intensity of 10,000 lux. Some light boxes put out lower intensities of 5,000 or even 2,500 lux. Why is this a problem? To get the full benefits, you need exposure to 10,000 lux for 30 minutes a day. If you choose a box that emits only 5,000 lux, you’ll have to stay in front of it twice as long. Unless you want to spend an hour or more in front of your box, choose one with an intensity of 10,000 lux.

Consider the Source of the Light
In the past, light boxes have emitted incandescent or fluorescent light. Now there are light-emitting diodes or LED lamps. There are advantages to LED over fluorescent light. Fluorescent light is made up of ultraviolet rays that you don’t want. Fluorescent light boxes from reputable manufacturers have a filter that filters out these damaging rays, but you can avoid this entirely by buying an LED box. LED emits light in a narrower spectrum that doesn’t include ultraviolet rays, so there’s no need for a filter. Plus, LED units are more efficient and lighter in weight than light boxes that use fluorescent light. With LED, you can get the same benefits with a lighter unit.

What about compact units? There are disadvantages to buying a compact unit. When a unit is smaller, you have to direct your gaze towards a smaller area. Turning your head slightly takes you out of the light field.

Avoid Blue Light Therapy for Now
You can now find light therapy boxes that emit only blue light. These were developed after some studies showed it may be more effective for treating seasonal affective disorder. Avoid systems that radiate only blue light for now. The retina in your eye is exquisitely sensitive to blue light and using one of these units could be damaging to your eyes. Choose a light box that emits white light for safety reasons until we know more about the benefits versus the risks of focused blue light.

Think about Where You’re Going to Put It
You’ll need to position your light box a little more than arm’s length from you, just above eye level. Think about where you’re going to put it. Some people place it on a platform on a desk so it’s above eye level or mount it on a wall in front of where they sit. If it’s electronically-powered, you’ll need to have a power source to plug it in and an area that’s free of moisture as well as enough room so that the ventilation slots in the back are unobstructed. You can also buy battery-operated models that don’t need to be plugged in.

Do You Need Added Features?
As with most devices, light boxes come with added features like a programmable timer, a rechargeable battery (for battery-operated models), the ability to change the light intensity, a stand or the wall-mounting accessories etc. As expected, you’ll pay more for these features. Ask yourself whether you really need these features before making your final selection.

The Bottom Line?
Many people find light boxes effective for treating the symptoms of adult ADHD, but don’t buy only based on price. Not all light boxes are the same. Keep the above factors in mind when making your selection. I’ve been very happy with the Sunlight Jr. Therapeutic Light Box. I’ve noticed a big effect, the box is very durable and has a small footprint.

Rybak, Y.E., McNeely, H.D., Mackenzie, B.E., Jain, U.R., & Levitan, R.D. (2006). An Open Trial of Light Therapy in Adult Attention Deficit/Hyperactivity Disorder. Journal of Clinical Psychiatry, 67(10), 1527-1535.


  1. In the study they used thirty minutes of light therapy, using a full-spectrum fluorescent light box. The Philips unit that you use is not a full spectrum light source and therefor you are risking damage to your eyes. Full Spectrum light is recommended for therapy because you are using a very bright light and full spectrum is the best light that your eyes can get.

  2. Thanks for the additional information Treasa!

  3. I would like to start using light therapy for ADHD. I purchased a small lamp and a 25 Watt blue light bulb. Will this be of any help for me will it make a difference if I use it for just a few minutes a day or would you recommend more wattage like a 50 or 75 Watt Bulb and a longer time period in front of the light?

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