light therapy

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Example of light therapy for winter depression

A light therapy is a recognized by the scientific medicine method for the treatment of various diseases. The care guideline for unipolar depression recommends light therapy especially for depression that follows a seasonal pattern. For depressive disorders that are not seasonally dependent, an efficacy can be demonstrated, but because of the small sample size, no treatment recommendation can yet be made in the guideline.

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Depression walkthrough

Modern light therapy lamp in operation

Therapeutically, the patients are exposed to bright artificial light ( daylight lamp ), which is also referred to as a light shower. Light therapy is best used immediately after awakening. The effectiveness has been well proven at an exposure of 10,000  lux for half an hour, or 2,500 lux for two hours. You should sit no more than 50–80 cm from the light source . It is important that the light falls on the retina . Therefore, the eyes must be open and must not be covered by sunglasses or anything else. However, the patient should not look directly into the light source.

Effective light colors

The spectral effectiveness of light therapy is not precisely known. A study from 1997 examined which light colors would have an influence on light therapy. Light with short or medium wavelengths (blue, green, yellow) seem to be necessary for a therapeutic effect, red light and UV light would be relatively ineffective, UV light can therefore be filtered out.

Effective latency and duration of action

An improvement is already measurable after a week, although it can take four weeks for the light therapy to respond completely (response). Of the patients with seasonally dependent depression, 60–90% respond to light therapy, which is evident within 2 to 3 weeks. After discontinuing light therapy, not all but most of the patients show a rapid return of the symptoms, which is why continuation of light therapy is recommended during the time of year with an increased risk.

application areas

In the guideline “Unipolar Depression” of the German Society for Psychiatry, Psychotherapy and Neurology ( DGPPN ), light therapy is one of the treatment options “first choice for seasonally dependent depression”. The preferred device for light therapy is a light source that emits white, fluorescent light from which the UV component is filtered out and that generates at least 2,500 lux. The guideline is based on a meta-analysis from 2005, which evaluated 23 randomized controlled studies.

There is also data to suggest that light therapy is effective for forms of non-seasonal depression. A Cochrane review based on 49 randomized controlled trials came to the conclusion that light therapy had a small, albeit demonstrable, efficacy in non-seasonal depression. However, due to the small sample size and the short treatment times, the DGPPN guideline has not yet made a recommendation for use in non-seasonal depression.

Alternatively, a method similar to light therapy is also used to prevent jet lag . Some airlines offer their long-haul passengers special headgear to which a bright light source is attached.

Suspected mechanisms of action

Light intensity of a light therapy lamp in a room into which the shady daylight can only be filtered through a curtain and penetrated through a window under a raised roof: Modern people often don't spend enough time outdoors, where the light is significantly brighter than in closed rooms

More recent studies deal with the connection between light therapy and circadian rhythms , for example with the combination of light therapy and sleep deprivation therapy (so-called waking therapy) and shifting the sleep phase forward. An important biological process seems to be that melatonin is produced in the brain, especially in the second half of the night . Melatonin is associated with a depressiogenic effect. If light therapy is applied immediately after waking up in the morning, i.e. as early as possible, the production of melatonin is stopped or melatonin is broken down, so that there is a positive change in mood. It has also been proven that light has an inhibitory effect on the melatonin balance.

Usually white light is used, which corresponds to the spectrum of sunlight. Normal daylight (even when the sky is overcast) is at least as effective as artificial light (light therapy lamp). Studies have shown, however, that many people do not spend enough time outdoors to expose themselves to the necessary amount of light.

A narrow frequency band in the blue light range of white light (wavelengths 446–477 nm), which acts on the blue light-sensitive photopigment melanopsin in the ganglion cells of the retina, is physiologically effective . Unlike the visual pigments in the rods and cones of the retina, melanopsin is not involved in visual perception, but influences the release of melatonin and, moreover, the circadian rhythm .

Contraindications

An ophthalmological examination will be carried out in the case of pre-existing diseases of the eye or the retina (e.g. detachment of the retina , retinitis pigmentosa ), systemic diseases that affect the retina (e.g. diabetes mellitus ), previous cataract operations or removal of the lens , and in general for older people Recommended for people due to the increased risk of age-related macular degeneration .

A contraindication can also be the use of one of the following drugs, as they increase photosensitivity: neuroleptics ( phenothiazines ), antidepressants ( imipramine ), phase prophylactics ( lithium ), diuretics ( hydrochlorothiazide ), methoxsalen , heart medication ( propranolol , amiodarone ), chloroquine , antibiotics ( Tetracyclines ), as well as St. John's wort as a herbal remedy for the treatment of depression .

Assumption of costs

For those with statutory health insurance in Germany, light therapy for the treatment of winter depression is always a self-pay benefit ( IGeL ). The IGeL monitor of the MDS ( Medical Service of the Central Association of Health Insurance Funds ) rates light therapy for seasonal depressive disorder as “generally positive”. Although the investigations and reviews that were found did not provide “a uniform picture of the benefits of the therapy”, some of the investigations and reviews that were evaluated showed that light therapy alleviated the symptoms of depression somewhat better than sham treatment. Headaches, tiredness and similar complaints, on the other hand, are no more common than with sham treatment. The light radiation no longer contains any UV, so it is harmless.

literature

Web links

Commons : Light Therapy  - Collection of Images, Videos and Audio Files

Individual evidence

  1. ↑ a b c d e f S3 guideline for unipolar depression of the DGPPN. In: AWMF online (as of 2015)
  2. ↑ TMCLee, CCHChan, JGPaterson, HLJanzen, CABlashko: Spectral properties of phototherapy for seasonal affective disorder: a meta ‐ analvsis ; Acta Psychiatrica Scandinavia, Volume 96, Issue 2, August 1997, pages 117-121
  3. Jump up ↑ Robert N. Golden, Bradley N. Gaynes, R. David Ekstrom, Robert M. Hamer, Frederick M. Jacobsen, Trisha Suppes, Katherine L. Wisner, Charles B Nemeroff: The Efficacy of Light Therapy in the Treatment of Mood Disorders: A Review and Meta-Analysis of the Evidence. In: The American Journal of Psychiatry 2005. 162 (4): 656-62. doi: 10.1176 / appi.ajp.162.4.656
  4. ↑ Terman M, Terman JS: Light therapy for seasonal and nonseasonal depression: efficacy, protocol, safety, and side effects Archived from the original on March 4, 2016. (PDF) In: CNS Spectr . 10, No. 8, August, pp. 647-63; quiz 672. Retrieved September 16, 2014. (Eng.)
  5. ↑ http://www.sciencenews.org/articles/20050423/fob7.asp (Engl.)
  6. ↑ S. Sekharan, J. Wei, V. Batista: The Active Site of melanopsin: The Biological Clock photoreceptor . In: J. Am. Chem. Soc. , Volume 134, 2012, pp. 19536-19539, doi: 10.1021 / ja308763b .
  7. ↑ SL Chellappa, R. Steiner, P. Blattner, P. Oelhafen, T. Götz et al .: Non-Visual Effects of Light on Melatonin, Alertness and Cognitive Performance: Can Blue-Enriched Light Keep Us Alert? . In: PLoS ONE , 2011, Volume 6, Number 1, e16429, doi: 10.1371 / journal.pone.0016429
  8. ↑ Christine Blume, Corrado Garbazza, Manuel Spitschan: Effects of light on human circadian rhythms, sleep and mood . In: Somnology . tape 23 , no. 3 , September 2019, ISSN  1432-9123 , p. 147–156 , doi : 10.1007 / s11818-019-00215-x , PMID 31534436 , PMC 6751071 (free full text).
  9. ↑ Christian Cajochen: Chronobiology: light and wake therapy for psychiatric diseases . In: PSYCH up2date . tape 7 , no. 03 , May 17, 2013, ISSN  2194-8895 , p. 173-184 , doi : 10.1055 / s-0033-1343181 .
  10. ↑ IGeL-Monitor: Light therapy for seasonal depressive disorder ("winter depression") , accessed on February 15, 2019. More on the justification for the assessment in the results report , accessed on February 15, 2019.