Before You Buy a Light Box

Not all light boxes meet the recommended requirements for treating SAD

Woman doing a light therapy session. France
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There are many light box products on the market that claim to help seasonal affective disorder (SAD), but here is what you should know before you buy a light box. Not all light boxes meet the recommended requirements for treating SAD.

What is Seasonal Affective Disorder?

Seasonal affective disorder (SAD) is a type of depression that's related to changes in seasons — SAD begins and ends at about the same times every year.

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. Less often, SAD causes depression in the spring or early summer.

Treatment for SAD may include light therapy (phototherapy), psychotherapy and medications.

Don't brush off that yearly feeling as simply a case of the "winter blues" or a seasonal funk that you have to tough out on your own. Take steps to keep your mood and motivation steady throughout the year.

In most cases, SAD symptoms appear during late fall or early winter and go away during the sunnier days of spring and summer. However, some people with the opposite pattern have symptoms that begin in spring or summer. In either case, symptoms may start out mild and become more severe as the season progresses.

Major depression

Seasonal affective disorder is a subtype of major depression that comes and goes based on seasons.

So symptoms of major depression may be part of SAD, such as:

  • Feeling depressed most of the day, nearly every day
  • Feeling hopeless or worthless
  • Having low energy
  • Losing interest in activities you once enjoyed
  • Having problems with sleeping
  • Experiencing changes in your appetite or weight
  • Feeling sluggish or agitated
  • Having difficulty concentrating
  • Having frequent thoughts of death or suicide

Fall and winter SAD

Symptoms specific to winter-onset SAD, sometimes called winter depression, may include:

  • Irritability
  • Tiredness or low energy
  • Problems getting along with other people
  • Hypersensitivity to rejection
  • Heavy, "leaden" feeling in the arms or legs
  • Oversleeping
  • Appetite changes, especially a craving for foods high in carbohydrates
  • Weight gain

Spring and summer SAD

Symptoms specific to summer-onset seasonal affective disorder, sometimes called summer depression, may include:

  • Depression
  • Trouble sleeping (insomnia)
  • Weight loss
  • Poor appetite
  • Agitation or anxiety

Before You Buy a Light Box for SAD

These are the requirements recommended by the Center for Environmental Therapeutics (CET) for effective light box therapy. Make sure that any unit you purchase meets these specifications.

Clinical Testing

The light box that you buy should have data from peer-reviewed clinical trials backing it up.

    Sufficient Output

    When you are seated at a comfortable distance from the light box, it should provide you with 10,000 lux of illumination.

    Avoid products which missing or unverified specifications.

      UV Filters

      Fluorescent lamps should have a smooth diffusing screen to filters out harmful ultraviolet (UV) rays.

        White Light Only

        Boxes that emit white light are preferred over "full spectrum" lamps and blue lamps, which do not provide any known advantage.

          Minimize Glare

          In order to minimize glare, the light should be projected downward toward the eyes at an angle.

            Sufficient Size

            A larger light box is better because even small head movements can take the eyes out of the therapeutic range of the light when a smaller light box is used.


            Mayo Clinic. Seasonal Affective Disorder.

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