How Light Therapy Works for Season Affective Disorder (SAD)

Light Therapy boxes work to generate a simulation of sunlight for people experiencing Seasonal Affective Disorder (SAD). Melanopsin receptors in the eyes trigger the compulsory serotonin release inside the brain for natural sleep cycles and overall impressions of well-being. Essentially, getting that “sunlight” in the morning when it is still dark outside can help to reset your circadian rhythm.

For a SAD Lamp to be effective, it has to emit light with a minimum of 2,500 lux (the unit of intensity that light is measured in). SAD bulbs were specifically made for use in SAD lighting, as the light in the bulbs are warmer on the eyes, allowing for quicker treatment of what you need, without harm.

More recently LED SAD lights have become more common, as they emit 10,000 lux and last considerably longer before needing to be replaced. The major benefit of the higher lux is that the greater intensity of light reduces treatment time, yet is equally as successful. This is great for individuals that lead active lifestyles and can’t sit in front of a light for at least thirty minutes in the morning.

To get the adequate amount of treatment from light therapy, the device needs to be at a certain distance in front of you, normally to your side so that it is within your peripheral vision. This will prevent any damage to the eyes. Different SAD lights may have different required distances depending on the precise lux they emit (among other factors), so shop around to make sure you get the light box that works best for you. Always be sure to follow directions for your lamp.

SAD lights are generally used in the morning in order to simulate the rising sun and rebalance your circadian rhythm. If needed, using one in the afternoon will likely make you feel awake through the evening—similar to taking a nap.

After regular use of a SAD light, symptoms will begin to lessen. Your circadian rhythm should come back to normal, providing you combine it with a healthy lifestyle and any other treatment that your healthcare professional has suggested.

More Information

A light therapy box is made up of a pair of fluorescent bulbs installed inside a box with a diffused screen. Many people place light boxes on an easily accessible table, desk, or nightstand. It is best to sit in front of the lamp for 15-30 minutes each morning. Looking at the lights isn’t recommended; instead, you are free to engage in these tasks while reading, writing, watching TV, browsing the Internet, or eating food. Treatments can be once or twice each day, depending on personal needs. Keep in mind that the typical length of a session utilizing a box delivering 10,000 lux will be, for example, much shorter than compared to 2,500 lux (30 minutes vs. two hours).

In clinical trials, one hundred individuals with SAD used a 10,000-lux system with UV-filtered light diffusion for 30 minutes every day. Of that trial, roughly 3/4 showed significant improvement of depressive symptoms. In a second experiment, it was discovered that thirty minutes was an adequate exposure time for some patients, whereas several required hour-long exposures to experience positive effects. Like most treatments related to mental health, it is important to assess how your body reacts to such treatment, to determine which therapy is best for you.

Research shows that unlike typical florescent bulbs or incandescent light, “full-spectrum” bulbs successfully simulate outside daylight. Manufacturers are now providing effective boxes that use cool-white, triphosphor and bi-axial lamps. The most important factor, however, is to find a bulb that simulates the outdoors soon after sunrise or before sunset. Light intensity is an essential “dosing” of the therapy—systems deliver varying levels of light, and responses may vary depending on the person.

Another important factor of light therapy treatment is when to undergo treatment “sessions”. Many people with winter depression respond best to therapy first thing in the morning. Some, however, do better with evening light. It is important to determine which part of day would be most beneficial for you and your habits, and then make a routine of it.

Some light-sensitive people who live and work in dim environments may feel improvement with increased exposure to normal room lighting. However, research studies show that many sufferers of SAD and winter blues need exposure to levels considerably greater than typical indoor lamps. Such levels are five to twenty times greater than typical indoor lighting in the home or workplace.

Some people undergo treatment by spending more time in sunlight. However, adequate sunlight is often unavailable for most of the winter months. The most powerful therapeutic effect requires exposure to artificial bright light in early morning hours when it is still quite dark outdoors during long winter nights.

Do the lights work?

Improvement in mood and energy is typically seen within the first week. Keep in mind that symptoms may come back with discontinued use or a break in routine. Most light therapy users keep a constant daily schedule beginning as early as autumn and continue until the outdoor light is sufficient enough to maintain good mood and high energy, typically into April. Some folks may skip remedies for a few days, occasionally longer, with no ill effect, but many begin to sag quickly when treatment is interrupted.

How does light therapy work?

Light therapy is known to have many benefits. Blood levels of the adrenal hormone melatonin, which might be dangerously high at certain times of day, are rapidly reduced by light exposure. When bright light is introduced to the body, our internal clock (which controls daily rhythms of body temperature, hormone secretion and sleep routines) begins to regulate. These physiological time shifts may be the basis of the therapeutic response. Light may also amplify the day-night gap in these types of rhythms. Research into the probable mechanisms is currently underway.

Are there any side effects?

Side effects are minimal. While a tiny minority of people experience migraines, eyestrain/irritation, or nausea at the beginning of treatment, side effects are generally mild and lighten up after a couple of days. The most noticeable side effect, which happens quite rarely, is a change into an overactive state, through which one may have difficulty sleeping, become irritable or restless, and feel speedy or “too high”. It is important to follow directions carefully, and listen to your body. If something feels off, discontinue use and talk to your doctor.

If an eye irritation persists, it may be alleviated by sitting further away from the lights or using them for shorter intervals. You may also look into different types of light boxes, perhaps with a lower lux capacity. Some people report sensations of “visual warmth” under bright light treatment, which may be alleviated by using a tilted light box layout. A major source of visual warmth is short-wavelength blue lighting, which can be a part of the lighting used for treatment. You may control the effects of blue lights by using a special, recently-developed “see-more” eyeglass lens, which maximizes transmission of longer wavelengths without considerably affecting lux levels.

What if I’m pregnant or nursing?

It is common for women who are pregnant or were recently pregnant to feel maternal depression totally unrelated from SAD. Many studies regarding pregnant women and light therapy have been conducted. Scientists hypothesize that women who experience maternal depression and development a routine using lightbox therapy will alleviate symptoms of depression within six weeks. As always, talk to your doctor about which light therapy treatment would be best for you, especially as a pregnant mother.

Do the lights cause tanned skin or damage?

They shouldn’t. Most light treatment methods shield outside (or substantially decrease) ultraviolet light which causes tanning. Occasionally, a person with very sensitive skin shows reddening under full-spectrum lights, in which case, using filters, alternate bulbs, or even a sun screen cream is needed. This should not affect the effectiveness of the treatment.

What is the history of light therapy?

Light therapy treatments began in the early 1980s. Thousands of patients have been carefully studied, demonstrating that light therapy treatment is well on its way to being an effective treatment of Seasonal Affective Disorder. Though not in widespread use, the number of clinician and therapist interest increases each year.

Is light therapy medically approved? Is a prescription required? Is it covered by insurance?

Light therapy is “medically approved” if your doctor recommends or suggests it, and if the procedure is approved. However, the Food and Drug Administration (FDA), has yet to approve of light therapy. A prescription is not required to undergo light therapy, but anybody suffering severe depression should seek a doctor’s recommendation before obtaining a light therapy box, and use it under the doctor’s supervision. Insurance reimbursement for the price of light therapy boxes is not typical. Medicaid does not yet cover this cost. In the case that your insurance plan covers psychiatric care or psychotherapy, it’s very likely that your provider will reimburse you for clinical sessions involved with identification of SAD, analysis for light therapy, and follow-ups.

How much are the lights? Can DIY light boxes be built?

Light box therapy is still young, though lots of manufacturers are coming out with new models every year. This means that light therapy boxes typically run between $30-$300, though with more technology and information, may become more affordable.

We don’t advocate home construction of the device. Output must be specifically calibrated to the appropriate therapeutic effect. Creating DIY electrical currents and heat can be dangerous. Light boxes on the marketplace must be tested for output strength, visual comfort, maximum transmission with minimal warmth build-up, and other safety concerns. These factors must be carefully checked before purchasing any light system.

What other treatments are available for SAD?

With recent unique technology advances, Negative Ion Therapy was proven to help alleviate symptoms associated with SAD. A negative ion is a molecule that contains an excess electron. These negatively-charged particles are created naturally from the sun, wind, and water. In high enough concentrations, these ions are capable of producing cleaner air. This has been shown to decrease irritability and depression in people with SAD, while improving their energy level.

Morning simulation is another type of light therapy that’s now being researched. In this therapy, one receives light exposure during the last cycle of sleep. A lamp is turned on with an automatic timer that simulates an actual outdoor springtime sunrise—sort of like an alarm clock on snooze, but with gradual lighting. This light, which is much less extreme than light boxes, has been tested to affect the human body’s biological clock, to suppress nitric oxide, and to have antidepressant effects. Both Negative Ion Therapy and Dawn Simulation Therapy can be treated while one is asleep. Because of this advantage, these treatment alternatives may be preferable.

Although an early study comparing light vulnerability to eyes and skin discovered that light in the eyes has the best therapeutic effect, a recent study suggests that circadian rhythms (the body’s biological clock) may be affected by mild exposure to light therapy boxes. While this finding will surely lead to additional research, it would be premature to draw conclusions concerning the possible effects of skin illumination on SAD symptoms. Also, people should take note that exposure to ultraviolet (UV) light, given off by sunlight and by tanning lamps, can result in other health complications, such as skin cancer. People with SAD should not try to “self-medicate” by exposing their skin potentially toxic UV illumination.

Besides these ecological therapies, some sufferers find that conventional antidepressant medications offer relief, even if they do not reach their normal degree of well-being until spring or summer. Many individuals have already been in psychotherapy and found it to be very helpful to them in several ways—but unfortunately, not in alleviating their SAD symptoms.

The best way to ensure success with a light box is to shop around and decide which light box would work best for your needs. Talk to your doctor or do extensive research online, and always follow instructions for individual light boxes. With most treatments of depression, patience is key: listen to your body.