DEAR MAYO CLINIC: Once daylight saving time ends, I find it difficult as it gets darker earlier. I also notice that I get a bit more depressed in the winter. My friend suggested a light box for seasonal affective disorder. What is a light box? And can it be helpful in improving my mood?

ANSWER: Seasonal affective disorder, or SAD, is a type of depression that typically occurs each year during fall and winter. If you're like most people with SAD, your symptoms start in the fall and continue into the winter months, sapping your energy and making you feel moody.

It is important not to brush off that yearly feeling as simply a case of the "winter blues" or a seasonal funk that you must tough out on your own. Take steps to keep your mood and motivation steady throughout the year.

The use of light therapy can offer relief. But, for some people, light therapy may be more effective when combined with another SAD treatment, such as an antidepressant or psychological counseling, or psychotherapy.

Light therapy boxes for SAD treatment also are known as light boxes, bright light therapy boxes and phototherapy boxes. All light therapy boxes for SAD treatment are designed do the same thing, but one type may work better for you than another.

A light therapy box mimics outdoor light. Researchers believe this type of light causes a chemical change in the brain that lifts your mood and eases other symptoms of SAD.

Generally, the light box should provide an exposure to 10,000 lux of light and emit as little ultraviolet, or UV, light as possible.

Typical recommendations include using the light box:

• Within the first hour of waking up in the morning.
• For about 20 to 30 minutes.
• At a distance of about 16 to 24 inches from the face.
• With eyes open, but not looking directly at the light.

Light boxes are designed to be safe and effective, but they aren't approved or regulated by the Food and Drug Administration for SAD treatment, so it's important to understand your options.

You can buy a light box without a prescription. Your health care provider may recommend a specific light box, but most health insurance plans do not cover the cost.

It's best to talk with your health care provider about choosing and using a light therapy box. If you're experiencing both SAD and bipolar disorder, the advisability and timing of using a light box should be carefully reviewed with your health care provider. Increasing exposure too fast or using the light box for too long each time may induce manic symptoms if you have bipolar disorder.

If you have past or current eye problems, such as glaucoma, cataracts or eye damage from diabetes, get advice from your eye care provider before starting light therapy.

Here are some questions to think about when buying a light box for seasonal affective disorder:

• Is it made specifically to treat SAD?
  If not, it may not help your depression. Some light therapy lamps are designed for skin disorders, not for SAD. Lamps used for skin disorders primarily emit UV light and could damage your eyes if used incorrectly. Light boxes used to treat SAD should filter out most or all UV light.
• How bright is it?
  Light boxes produce different intensities of light. Brighter boxes will require less time to use each day, compared with dimmer boxes, to achieve the same effect. Typically, the recommended intensity of light is 10,000 lux.
• How much UV light does it release?
  Light boxes for SAD should be designed to filter out most or all UV light. Contact the manufacturer for safety information if you have questions.
• Can it cause eye damage?
  Some light boxes include features designed to protect the eyes. Make sure the light box filters out most or all UV light to avoid damaging your eyes. Ask your eye care provider for advice on choosing a light box if you have eye problems, such as glaucoma, cataracts or eye damage from diabetes.
• Is it the style you need?
  Light boxes come in different shapes and sizes, with varied features. Some look like upright lamps, while others are small and rectangular. The effectiveness of a light box depends on daily use, so buy one that's convenient for you.
• Can you put it in the right location?
  Think about where you'll want to place your light box and what you might do during its use, such as reading. Check the manufacturer's instructions, so you receive the right amount of light at the proper distance.

Again, talk to your health care professional about light box options and recommendations, so you get one that's best suited to your needs. — Compiled by Mayo Clinic staff

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Related Articles 

• Mayo Clinic Minute: Light therapy can help with seasonal affective disorder published 12/21/21
• Consumer Health: What do you know about seasonal affective disorder? published 11/11/21
• Mayo Clinic Minute: Does daylight saving time change disrupt your health? published 11/5/21
• Consumer Health: Daylight saving time change can disrupt your good night’s sleep published 11/4/21

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