Light therapy

Definition

Light therapy, or phototherapy, is the administration of doses of bright light in order to treat a variety of sleep and mood disorders. It is most commonly used to re-regulate the body's internal clock and/or relieve depression.

Origins

Light, both natural and artificial, has been prescribed throughout the ages for healing purposes. Sunlight has been used medicinally since the time of the ancient Greeks; Hippocrates, the father of modern medicine, prescribed exposure to sunlight for a number of illnesses. In the late nineteenth and early twentieth centuries, bright light and fresh air were frequently prescribed for a number of mood and stress related disorders. In fact, prior to World War II, hospitals were regularly built with solariums, or sun rooms, in which patients could spend time recuperating in the sunlight.

In the 1980s, light therapy began to make an appearance in the medical literature as a treatment for seasonal affective disorder, or SAD. Today, it is widely recognized as a front-line treatment for the disorder.

Benefits

Light therapy is most often prescribed to treat seasonal affective disorder, a form of depression most often associated with shortened daylight hours in northern latitudes from the late fall to the early spring. It is also occasionally employed to treat such sleep-related disorders as insomnia and jet lag. Recently, light therapy has also been found effective in the treatment of such nonseasonal forms of depression as bipolar disorder. One 2001 study found that bright light reduced depressive symptoms 12–35% more than a placebo treatment in nine out of 10 randomized controlled trials.

When used to treat SAD or other forms of depression, light therapy has several advantages over prescription antidepressants. Light therapy tends to work faster than medications, alleviating depressive symptoms within two to 14 days after beginning light therapy as opposed to an average of four to six weeks with medication. And unlike antidepressants, which can cause a variety of side effects from nausea to concentration problems, light therapy is extremely well tolerated. Some side effects are possible with light but are generally not serious enough to cause discontinuation of the therapy.

There are several other different applications for light therapy, including:

• Full-spectrum/UV light therapy for disorders of the skin. A subtype of light therapy that is often prescribed to treat skin diseases, rashes, and jaundice.
• Cold laser therapy. The treatment involves focusing very low-intensity beams of laser light on the skin, and is used in laser acupuncture to treat a myriad of symptoms and illnesses, including pain, stress, and tendinitis.
• Colored light therapy. In colored light therapy, different colored filters are applied over a light source to achieve specific therapeutic effects. The colored light is then focused on the patient, either with a floodlight which covers the patient with the colored light, or with a beam of light that is focused on the area of the illness.
• Back of knee light therapy. A 1998 report published in the journal Science reported that the area behind the human knee known as the popliteal region contains photoreceptors that can help to adjust the body's circadian rhythms. The authors of the study found that they could manipulate circadian rhythms by focusing a bright light on the popliteal region. Further studies are needed to determine the efficacy of this treatment on disorders such as SAD and jet lag.

Description

Light therapy is generally administered at home. The most commonly used light therapy equipment is a portable lighting device known as a light box. The light box may be a full-spectrum box, in which the lighting element contains all wavelengths of light found in natural light (including UV rays), or it may be a bright light box, in which the lighting element emits non-UV white light. The box may be mounted upright to a wall, or slanted downwards towards a table.

The patient sits in front of the box for a prescribed period of time (anywhere from 15 minutes to several hours). For patients just starting on the therapy, initial sessions are usually only 10–15 minutes in length. Some patients with SAD undergo light therapy session two or three times a day, others only once. The time of day and number of times treatment is administered depends on the physical needs and lifestyle of the individual patient. If light therapy has been prescribed for the treatment of SAD, it typically begins in the fall months as the days begin to shorten, and continues throughout the winter and possibly the early spring. Patients with a long-standing history of SAD are usually able to establish a timetable or pattern to their depressive symptoms, and can initiate treatment accordingly before symptoms begin.

The light from a slanted light box is designed to focus on the table it sits upon, so patients may look down to read or do other sedentary activities during therapy. Patients using an upright light box must face the light source, and should glance toward the light source occasionally without staring directly into the light. The light sources in these light boxes typically range from 2,500–10,000 lux (in contrast, average indoor lighting is 300–500 lux; a sunny summer day is about 100,000 lux).

Light boxes can be purchased for between $200 and $500. Some healthcare providers and healthcare supply companies also rent the fixtures. This gives a patient the opportunity to have a trial run of the therapy before making the investment in a light box. Recently, several new light box products have become available. Dawn simulators are lighting devices or fixtures that are programmed to turn on gradually, from dim to bright light, to simulate the sunrise. They are sometimes prescribed for individuals who have difficulty getting up in the morning due to SAD symptoms. Another device known as a light visor is designed to give an individual more mobility during treatment. The visor is a lighting apparatus that is worn like a sun visor around the crown of the head. Patients with any history of eye problems should consult their healthcare professional before attempting to use a light visor.

Preparations

Full-spectrum light boxes do emit UV rays, so patients with sun-sensitive skin should apply a sun screen before sitting in front of the box for an extended period of time.

Precautions

Patients with eye problems should see an ophthalmologist regularly both before and during light therapy. Because UV rays are emitted by the light box, patients taking photosensitizing medications should consult with their healthcare provider before beginning treatment. In

addition, patients with medical conditions that make them sensitive to UV rays should also be seen by a healthcare professional before starting phototherapy.

Patients beginning light therapy for SAD may need to adjust the length, frequency, and timing of their phototherapy sessions in order to achieve the maximum benefits. Patients should keep their healthcare provider informed of their progress and the status of their depressive symptoms. Occasionally, additional treatment measures for depression (i.e., antidepressants, herbal remedies, psychotherapy) may be recommended as an adjunct, or companion treatment, to light therapy.

Side Effects

Some patients undergoing light therapy treatments report side effects of eyestrain, headaches, insomnia, fatigue, sunburn, and dry eyes and nose. Most of these effects can be managed by adjusting the timing and duration of the light therapy sessions. A strong sun block and eye and nose drops can alleviate the others. Long-term studies have shown no negative effects to eye function of individuals undergoing light therapy treatment.

A small percentage of light therapy patients may experience hypomania, a feeling of exaggerated, hyperelevated mood. Again, adjusting the length and frequency of treatment sessions can usually manage this side effect.

Research & General Acceptance

Light therapy is widely accepted by both traditional and complementary medicine as an effective treatment for SAD. The exact mechanisms by which the treatment works are not known, but the bright light employed in light therapy may act to readjust the body's circadian rhythms, or internal clock. Other popular theories are that light triggers the production of serotonin, a neurotransmitter believed to be related to depressive disorders, or that it influences the body's production of melatonin, a hormone that may be related to circadian rhythms. A recent British study suggests that dawn simulation, a form of light therapy in which the patient is exposed to white light of gradually increasing brightness (peaking at 250 lux after 90 min) may be even more effective in treating depression than exposure to bright light. Dawn simulation is started around 4:30 or 5 o'clock in the morning, while the patient is still asleep.

Wide-spectrum UV light treatment for skin disorders such as psoriasis is also considered a standard treatment option in clinical practice. However, such other light-related treatments as cold laser therapy and colored light therapy are not generally accepted, since few or no scientific studies exist on the techniques.

Training & Certification

Psychiatrists, psychologists, and other mental healthcare professional prescribe light therapy treatment for SAD. Holistic healthcare professionals and light therapists who specialize in this treatment are also available; in some states, these professionals require a license, so individuals should check with their state board of health to ensure their practitioner has the proper credentials. Light therapy for skin disorders should be prescribed by a dermatologist or other healthcare professional with expertise in skin diseases and light therapy treatment.

Resources

Books

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington, DC: American Psychiatric Press, Inc., 1994.

Lam, Raymond, ed. Seasonal Affective Disorder and Beyond: Light Treatment for SAD and Non-SAD Conditions. Washington, DC: American Psychiatric Press, 1998.

Rosenthal, Norman. Winter Blues: Seasonal Affective Disorder—What It Is and How to Overcome It. New York: Guilford Press, 1998.

Periodicals

Eagles, John M. "SAD—Help Arrives with the Dawn?" Lancet 358 (December 22, 2001): 2100.

Jepson, Tracy, et al. "Current Perspectives on the Management of Seasonal Affective Disorder." Journal of the American Pharmaceutical Association. 39 no. 6 (1999): 822–829.

Sherman, Carl. "Underrated Light Therapy Effective for Depression." Clinical Psychiatry News 29 (October 2001): 32.

Organizations

National Depressive and Manic Depressive Association. 730 Franklin Street, Suite 501, Chicago, IL 60610. (800) 826-3632. .

Society for Light Treatment and Biological Rhythms. 824 Howard Ave., New Haven, CT 06519. Fax (203) 764-4324. . sltbr@yale.edu.

[Article by: Paula Ford-Martin; Rebecca J. Frey, PhD]

Bright light therapy is a common treatment for seasonal affective disorder and for circadian rhythm disorders.

Light therapy or phototherapy consists of exposure to daylight or to specific wavelengths of light using lasers, light-emitting diodes, fluorescent lamps, dichroic lamps or very bright, full-spectrum light, for a prescribed amount of time and, in some cases, at a specific time of day. Light therapy directed at the skin is used to treat Acne vulgaris and neonatal jaundice. Light therapy which strikes the retina of the eyes is used to treat circadian rhythm disorders such as delayed sleep phase syndrome. Bright light to the eyes treats seasonal affective disorder, with some support for its use also with non-seasonal psychiatric disorders.

Contents 1 Skin related 1.1 Acne vulgaris 1.2 Psoriasis and eczema 1.3 Tanning 1.4 Wound healing 1.5 Photodynamic therapy 2 Mood and sleep related 2.1 Light boxes 2.2 Seasonal affective disorder 2.3 Non-seasonal depression 2.4 Circadian rhythm sleep disorders 2.4.1 Chronic CRSD 2.4.2 Situational CRSD 3 Neonatal jaundice 4 Parkinson's disease 5 Safety 5.1 Side effects 6 See also 7 References

Skin related

Acne vulgaris

Sunlight was long known to improve acne, and this was thought to be due to antibacterial and other effects of the ultraviolet spectrum; which cannot be used as a treatment due to the likelihood of skin damage in the long term. However, artificial UV didn't work as well as sunlight.

It was found that some of the visible violet light, present in sunlight, in the range 405-420 nm activates a porphyrin (Coproporphyrin III) in Propionibacterium acnes which damages and ultimately kills the bacteria by releasing singlet oxygen. A total of 320 J/cm² of light within this range renders the bacteria non-viable.^[1]

Deep penetrating light therapy for 3 consecutive days has been shown to reduce the bacteria in the pores by 99.9%. Since there are few porphyrins naturally found in the skin, the treatment is believed safe except in patients with porphyria;^[2] although eye protection is used due to light-sensitive chemicals in the retina. The light is usually created by fluorescent lamps, bright LEDs or dichroic filament bulbs.

Overall improvements of on average 76% for 80% of patients occurs over 3 months; most studies show that it performs better than benzoyl peroxide and the treatment is far better tolerated. However, approximately 10% of users see no improvement.^[1]

Psoriasis and eczema

A feature of psoriasis is localised inflammation mediated by the immune system. UV radiation is known to suppress the immune system and reduce inflammatory responses. Light therapy for skin conditions like psoriasis or eczema use UVA (315-400 nm waveband) or UVB (280-315 nm waveband) light waves. UVA, combined with a drug taken orally, is known as PUVA treatment. Narrow Band UVB is the 310 nm wave length and is given as a light therapy treatment rather than full spectrum UVB.

Tanning

Tanning is caused by the effects of two different spectrums of ultraviolet radiation: UVA and UVB.

Wound healing

Light therapy has been suggested used for the healing of wounds. Some^[3] say that it does not appear to be effective, while others^[4] find that it can be effective.

Photodynamic therapy

Visible blue light is used with aminolevulinic acid for the treatment of Actinic keratosis. This is not a U.S. FDA-approved treatment for acne vulgaris.^[5]

Mood and sleep related

Light boxes

For the purpose of manipulating melatonin levels or timing, light boxes providing intense artificial illumination are effective.^{[citation needed]} These lamps, at a prescribed distance and within peripheral vision, provide up to 10,000 lux to the user's eyes, without harmful ultraviolet radiation.

The production of the hormone melatonin, a sleep regulator, is inhibited by light and permitted by darkness. To some degree, the reverse is true for serotonin, which has been linked to mood disorders.

A lower intensity of certain wavelengths of light in the blue end of the electromagnetic spectrum, about 480 nm, may be as efficacious as high-intensity white light.^[6]

Seasonal affective disorder

While full sunlight is preferred for seasonal affective disorder (SAD) light boxes may be effective for the treatment of the condition. The United States Food and Drug Administration has not approved the use of light boxes to treat SAD due to unclear results in clinical trials,^[7] but light therapy is still seen as the main form of treatment for SAD.^[8]

It is possible that response to light therapy for SAD could be season dependent.^[9]

Non-seasonal depression

Light therapy has also been suggested in the treatment of non-seasonal depression and other psychiatric distrubances, including major depressive disorder, bipolar disorder and postpartum depression.^[10][11]

Circadian rhythm sleep disorders

Chronic CRSD

In the management of circadian rhythm disorders such as delayed sleep phase syndrome, the timing of light exposure is critical. For DSPS, the light must be provided as soon after spontaneous awakening as possible to achieve the desired effect, as shown by the phase response curve for light in humans. Some users have reported success with lights that turn on shortly before awakening (dawn simulation). Morning use may also be effective for non-24-hour sleep-wake syndrome, while evening use is recommended for advanced sleep phase syndrome.

Situational CRSD

Light therapy has been tested for individuals on shift work,^[12] and for jet lag.^[13]

Neonatal jaundice

A newborn infant undergoing white-light phototherapy to treat neonatal jaundice.

Light therapy is used to treat cases of neonatal jaundice^[14] through the isomerisation of the bilirubin and consequently transformation into compounds that the newborn can excrete via urine and stools.

Parkinson's disease

Bright light therapy may ease Parkinson's disease by reducing patients' tremors.^[15][16]

Safety

Ultraviolet light causes progressive damage to human skin. This is mediated by genetic damage, collagen damage, as well as destruction of vitamin A and vitamin C in the skin and free radical generation. Researchers have questioned whether limiting blue light exposure could reduce the risk of age-related macular degeneration.^[17]

Modern phototherapy lamps used in the treatment of seasonal affective disorder and sleep disorders either filter out or do not emit ultraviolet light and are considered safe and effective for the intended purpose, as long as photosensitizing drugs are not being taken at the same time and in the absence of any existing eye conditions. Light therapy is a mood altering treatment, and just as with drug treatments, there is a possibility of triggering a manic state from a depressive state, causing anxiety and other side effects. While these side-effects are usually controllable, it is recommended that patients undertake light-therapy under the supervision of an experienced clinician, rather than attempting to self-medicate.^[18]

It is reported that bright light therapy may activate the production of reproductive hormones, such as testosterone, luteinizing hormone, follicle-stimulating hormone, and estradiol.^[19][20]

There are few absolute contraindications to light therapy, although there are some circumstances in which caution is required. These include when a patient has a condition that might render his or her eyes more vulnerable to phototoxicity, has a tendency toward mania, has a photosensitive skin condition, or is taking a photosensitizing herb (such as St. John's wort) or medication.^[21] Patients with porphyria should avoid most forms of light therapy. Patients on certain drugs like methotrxate or chloroquine should use caution with light therapy as there is a chance that these drugs could cause porphyria.

Side effects

Side effects of light therapy for sleep phase disorders include jumpiness or jitteriness, headache, and nausea. Some nondepressive physical complaints (such as poor vision and skin rash or irritation) may improve with light therapy.^[22]

See also

• Low level laser therapy
• Deep penetrating light therapy

References

1. ^ ^{a b} Papageorgiou P, Katsambas A, Chu A (May 2000). "Phototherapy with blue (415 nm) and red (660 nm) light in the treatment of acne vulgaris". Br. J. Dermatol. 142 (5): 973–8. doi:10.1046/j.1365-2133.2000.03481.x. PMID 10809858. 
2. ^ Hebel, JL; Poh-Fitzpatrick MB (2009-01-12). "Congenital Erythropoietic Porphyria". eMedicine. http://www.emedicine.com/DERM/topic145.htm. Retrieved 2009-06-09. 
3. ^ Posten W, Wrone DA, Dover JS, Arndt KA, Silapunt S, Alam M (March 2005). "Low-level laser therapy for wound healing: mechanism and efficacy". Dermatol Surg 31 (3): 334–40. PMID 15841638. 
4. ^ Journal of Wound, Ostomy and Continence Nursing January/February 2008 Volume 35 Number 1 Pages 116 - 117 [1]
5. ^ Aetna policy bulletin re: Phototherapy for Acne
6. ^ Wright HR, Lack LC, Kennaway DJ (March 2004). "Differential effects of light wavelength in phase advancing the melatonin rhythm". J. Pineal Res. 36 (2): 140–4. doi:10.1046/j.1600-079X.2003.00108.x. PMID 14962066. 
7. ^ "Seasonal affective disorder (SAD) - Treatment and drugs". Mayo Clinic. 2007-09-24. http://www.mayoclinic.com/health/seasonal-affective-disorder/DS00195/DSECTION=treatments%2Dand%2Ddrugs. Retrieved 2009-06-09. 
8. ^ "Light therapy - why it's done". Mayo Clinic. 2008-10-07. http://www.mayoclinic.com/health/light-therapy/MY00195/DSECTION=why%2Dits%2Ddone. Retrieved 2009-06-09. 
9. ^ Thompson C, Stinson D, Smith A (September 1990). "Seasonal affective disorder and season-dependent abnormalities of melatonin suppression by light". Lancet 336 (8717): 703–6. doi:10.1016/0140-6736(90)92202-S. PMID 1975891. 
10. ^ Prasko J (November 2008). "Bright light therapy". Neuro Endocrinol. Lett. 29 Suppl 1: 33–64. PMID 19029878. 
11. ^ Terman M (December 2007). "Evolving applications of light therapy" (pdf). Sleep Med Rev 11 (6): 497–507. doi:10.1016/j.smrv.2007.06.003. PMID 17964200. http://www.chronobiology.ch/chronobiology.data/Dokumente/PDF/PDF_Chrono_Psychiatry/Terman_07.pdf. 
12. ^ Smith MR, Eastman CI (December 2008). "Night shift performance is improved by a compromise circadian phase position: study 3. Circadian phase after 7 night shifts with an intervening weekend off". Sleep 31 (12): 1639–45. PMID 19090319. 
13. ^ Brown GM, Pandi-Perumal SR, Trakht I, Cardinali DP (March 2009). "Melatonin and its relevance to jet lag". Travel Med Infect Dis 7 (2): 69–81. doi:10.1016/j.tmaid.2008.09.004. PMID 19237140. 
14. ^ Newman TB, Kuzniewicz MW, Liljestrand P, Wi S, McCulloch C, Escobar GJ (May 2009). "Numbers needed to treat with phototherapy according to American Academy of Pediatrics guidelines". Pediatrics 123 (5): 1352–9. doi:10.1542/peds.2008-1635. PMID 19403502. 
15. ^ Paus S, Schmitz-Hübsch T, Wüllner U, Vogel A, Klockgether T, Abele M (July 2007). "Bright light therapy in Parkinson's disease: a pilot study". Mov. Disord. 22 (10): 1495–8. doi:10.1002/mds.21542. PMID 17516492. 
16. ^ Willis GL, Turner EJ (2007). "Primary and secondary features of Parkinson's disease improve with strategic exposure to bright light: a case series study". Chronobiol. Int. 24 (3): 521–37. doi:10.1080/07420520701420717. PMID 17612949. 
17. ^ Glazer-Hockstein C, Dunaief JL (January 2006). "Could blue light-blocking lenses decrease the risk of age-related macular degeneration?". Retina (Philadelphia, Pa.) 26 (1): 1–4. PMID 16395131. 
18. ^ Terman M, Terman JS (August 2005). "Light therapy for seasonal and nonseasonal depression: efficacy, protocol, safety, and side effects". CNS Spectr 10 (8): 647–63; quiz 672. PMID 16041296. 
19. ^ "Bright Light May Boost Testosterone". WebMD. http://www.webmd.com/erectile-dysfunction/news/20030422/bright-light-may-boost-testosterone. Retrieved 2008-12-15. 
20. ^ Danilenko KV, Samoilova EA (2007). "Stimulatory effect of morning bright light on reproductive hormones and ovulation: results of a controlled crossover trial". PLoS Clin Trials 2 (2): e7. doi:10.1371/journal.pctr.0020007. PMID 17290302. 
21. ^ Gagarina, AK (2007-12-08). "Light Therapy Diagnostic Indications and Contraindications". American Medical Network. http://www.health.am/psy/more/light_therapy1/. Retrieved 2009-06-09. 
22. ^ Roger DR (2007-12-04). "Practical aspects of light therapy". American Medical Network. http://www.health.am/psy/more/light_therapy4/. Retrieved 2009-06-09. 

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