Light Therapy For SAD

Light therapy for SAD

Light therapy for SAD is the most common treatment used by millions of people around the world to treat the extra depression a lack of sunlight can give you. On this page we look to explain everything there is to know about light therapy for SAD and to provide you with enough information to make an informed decision before buying one of the many products available on the market today.`


What is SAD?

Seasonal affective disorder, more commonly referred to as SAD, also known as winter depression, winter blues, summer melancholy, summer doldrums, or seasonal depression, is a mood disorder subset by which individuals who have normal mental health during the majority of the year suddenly experience experience depressive symptoms during the darker months or even during cloudy days in the summer months.

What causes SAD?

It is not known exactly what causes SAD. It has been suggested that it is related to the fewer hours of daylight that occur during winter and the fall. Levels of chemicals and hormones in the brain (like melatonin and serotonin) are affected by this reduced exposure to sunlight. Serotonin helps lift mood, and melatonin your patterns sleep and also your mood. Individuals that suffer from SAD are believed to generate too much or too little of these compounds when their exposure to sunlight is reduced.

What are the symptoms of SAD?

  • Low disposition throughout the day
  • Tiredness
  • Increased time spent sleeping
  • An increase in appetite
  • Weight gain
  • Irritability
  • Trouble relating to others
  • A heavy feeling throughout the body
  • Suicidal thoughts (only in extraordinary cases)

What exactly is light therapy for SAD?

Exposure to specialized bright light help the body to stimulate production of brain chemicals that relieve some of the symptoms that are associated with SAD. In 2001, a team at Thomas Jefferson Medical University identified a photo receptor in the human eye that is responsible for controlling the bodies production of melatonin when it receives light.

Research has been done that shows symptoms can be improved by exposure to a suitably bright artificial light in 2/3 instances of SAD.

This artificial light comes from a light box, which is an artificial light source designed to produce the same wavelengths of light as natural sun. These light boxes emit up to 10,000 Lux (“Lux” is the unit of measurement for illuminance) which is the recommended amount to treat this disorder. Despite being so bright the light emitted does not harm the eyes as long as it is used correctly.

How long has this treatment been available?

The first noted clinical effect was found at the National Institute of Mental Health in the early 80’s. Soon after this, different research centers started clinical trials. Currently, over 2,000 SAD patients have been examined to date. This treatment has been used in private practices, mainly by psychiatrist (often early adopters of health technologies), but also by family doctors. The amount of doctors and clinicians now offering light treatment is growing dramatically, though in comparison to psychotherapy or drug treatments, the procedure isn’t yet in widespread use.

How do you use light therapy?

For most individuals, light therapy provides best effects if used each day, upon awakening. Most studies have demonstrated this to be more effective than evening light, when one timing is compared against the other and no further info is gathered about the patients participating.

You should sit with the light box in front of you so the light is shining in your face. You do not need to shine the light directly into your eyes. Most folks do their light therapy while performing every day sitting tasks such as working at a computer, reading, watching T.V or eating. The light should be put above eye level so the light reaches the bottom of your retina. Patients in a test group with light hitting on just the top of the retina (so the light is below eye level) didn’t react as well to the therapy.

Normally, treatment starts with session of between 10 to 15 minutes each day, which are slowly increased to around 45 minutes each day. Thus depending on the lux output of your light. The lower the lux output, the longer you have to spend under the light.

Because the autumn and winter months are are darkest, most people start light therapy for SAD early in the autumn and continue the treatment until late spring, when exposure to sunshine alone is enough.

How quickly does light therapy work?

Most individuals see an immediate improvement in around 3 days. If symptoms don’t improve after 4 to 6 weeks or get worse, you should speak to your doctor about additional treatment options.

Are there any side effects?

Light therapy for SAD can have some side effects. They are uncommon but can include:

  • Headache
  • Irritability
  • Fatigue
  • Difficulty sleeping (if used late in the day)
  • Eye strain

It’s possible to use a light box too much. Agitation and eyestrain for between 1-3 days seem to be the principal side effects. Inducing mania has been observed in about 1% of users with bipolar disorder.

Those with photosensitivity (either naturally or though medication) as well as those who wear contact lenses should be careful when beginning light therapy for SAD treatments.

Once light therapy works, those on antidepressants are often allowed by their doctor to lower their dosage. For most patients, light therapy has proven to be extremely cost effective and is classed as one of the safest and well as most natural treatments for SAD.

What to look for when buying a SAD light therapy device

Not all lights provide the same type or strength of light and there are many light therapy lamps available. Some lamps supply ultraviolet rays which is not recommended. UV light is limited (or blocked) by others, but generate a narrower band wavelength of light.

Lux Output

The quantity of light that reaches your eyeball from interior lighting is far less compared to the amount received from the sun. Unless you happen to be outside for most of the day in winter months, you might be relying on light produced from light bulbs for your photons.

Many light-therapy plans require a light sources to generate at least 10,000 lux, which is the same as being in daylight on a clear day. Each system differs, but most manufacturers require you this intensity of light for a minimum of 20 minutes daily. Sun lamps that provide a lower lux output may not give you enough the light to enable you to effectively treat SAD, however they may offer other advantages. Remember that unless the lamps are 10,000 lux they cannot be classed as strong enough to treat Seasonal Affective Disorder

Here is the lux output you receive from well known light sources. (The cloudy output depends on where you are in the world)

Bright moonlight 1 lux
Candle light at 20 cm 10-15 lux
Street light 10-20 lux
Normal living room lighting 100 lux
Office fluorescent light 300-500 lux
Sunlight, 1 hour before sunset 1000 lux
Daylight, cloudy sky 5000 lux
Daylight, clear sky 10,000-20.000 lux
Bright sunlight > 20,000-100,000 lux

The above table is taken from here

Bulb Spectrum

There are two main types of bulbs used in light therapy boxes. Full spectrum and broad spectrum.

The first type we will cover is full spectrum. The light emitted from such a bulb provides a similar spectrum of light to sunlight while offering many of the same benefits. There are some treatment plans that do not need a light that produces a full spectrum of light. Almost all light box manufacturers using these UV beams integrate a UV diffuser screen to block these UV rays.

The alternative is Broad spectrum. This form of light is as close to the complete spectrum of light that you can get but without emitting UV rays. These light bulbs are often described being a pure white in colour. Using a broad spectrum light box means there is not a danger of overexposure to UV rays. Most light box businesses use a broad spectrum light bulb.

Distance from the light source matters

Take note that a lot of light boxes that claim to be 10,00 lux often don’t tell you what distance you need to be from the light. Make sure you check the distance at which 10,000 lux is gained because there is big difference between models. Some claim 10,000 lux but require you to be inches away which is impractical. Others allow you to be a couple of feet away from the light source.

Size of the box

The key thing to remember here is that small isn’t always better. The overall size of the light box plays a huge part in how the apparatus can be used. Smaller often emit lower lux levels or as noted above require you to be very close to the light source. Smaller boxes can be convenient when travelling but are often impractical if you want to perform everyday tasks while using the light. It should also be noted that the smaller area of light a small light box provides means that if you move your head you may move out of the range or area of light that is being produced.

UV output

UV rays assist you to create Vitamin D however they could also damage your skin. There are many noted disadvantages to overexposure to UV rays so the potential harm occasionally outweighs the advantages. Because of this, many SAD lamps restrict UV beams completely. Other lamps need the exact same care you would take when exposing your body to direct sun and it’s UV rays. If the lamp you select does emit UV rays it is crucial that it comes fitted with an UV diffuser display that removes as much UV as possible.

LED light therapy for SAD

In the past few years LED light boxes designed to treat Seasonal Affective Disorder have proved to be equally as effective as traditional SAD Light apparatus fitted with traditional bulbs.

There have been some manufacturers who have latched onto this development and are making LED light boxes that do not meet the conditions met in the research. Some ‘copycat’ products, marketed at SAD sufferers do not produce the right lux output or wavelengths of light and while they are generally not dangerous they may efficiently treat Seasonal Affective Disorder. Please constantly examine the makers website and published literature thoroughly before you purchase one of these products as you need to be sure of exactly what you are buying.

Are dawn simulators effective for SAD?

Dawn Simulators do not do not emit anywhere near the 10,000 lux required to effectively treat SAD however they do help with some symptoms of SAD. Because of the low lux output they cannot be classed as a SAD Light.

A dawn simulator is a device used to help you gently wake up from sleep. Some of these simulator also include a Sunset feature to help getting to sleep. They are great products on their own, but they should not be confused with SAD Lights as they do not provide enough exposure to daylight rays and they treat only part of the issue. Dawn Simulators help you to get good sleep and aid you in wakening naturally in the mornings.

Lots of sufferers of Seasonal Affective Disorder buy both a Dawn Simulator and a SAD Light to be used in conjunction with one another. Waking using a Dawn Simulator and then immediately using a SAD light for around 30 minutes after you wake is one of the best way to treat SAD.

What about blue light therapy for sad?

Blue light is wavelength that sets biological rhythms, including sleep/wake cycles in people. Back around 2005, some businesses started making little blue light boxes. They could be smaller because they claimed only the “active ingredient” used in the white lights was being emitted by them.

There has been much debate about whether they are actually any good and up until very recently there hasn’t been an conclusive proof of their effectiveness. Mind you, there is certainly research demonstrating that a small blue box is preferable to a placebo.