Dark Therapy


 * This article is about the medical uses for the absence of light. For alternative uses see Darkness (disambiguation).

Dark therapy manipulates circadian rhythms to act on hormones and neurotransmitters. It has been proposed recently (2005) to combine the chronobiological manipulations of light/dark and/or sleep/wake therapies with psychopharmacological medication. In the words of Anna Wirz-Justice:
 * Light therapy has undergone widespread controlled randomized clinical trials, and wake therapy has been so widely studied over decades that the efficacy data are strong. These nonpharmaceutical, biologically based therapies are not only powerful adjuvants, but also antidepressants in their own right.

Treatment constraints
When having dark hours in at home or hospital, subjects will often be exposed to a lower number of light hours than in their usual environment, so they need to make the environment light tight. Light from most sources could disrupt dark therapy. Also, it is necessary to have dark therapy hours at the specified times during each day.

Virtual darkness
By using amber lenses, researchers were able to block blue spectrum light, which affected "physiology of human circadian rhythm ... suggesting a circadian effect". This effect was previously noted with "amber-tinted safety glasses" which "preserve normal nocturnal melatonin levels in a light environment which otherwise completely suppresses melatonin production". PMID 17637502

Clinical pharmacology
Researchers hypothesize that the benefits of being in the dark are due to melatonin production by the pineal gland, which occurs when the body is deprived of light, as shown during controlled light-dark cycles, even for blind subjects, indicating that melanopsin is responsible for circadian entrainment in humans.

Side effects
No side effects have been officially reported for Dark Therapy.

Bipolar disorder treatment
There was a single small scale study done in Hospital San Raffaele of Milan, in Italy, which concluded that chronobiological interventions and control of environmental stimuli can be a useful add-on for the treatment of acute mania in a hospital setting. Further examinations were done on single patients, and are reported on the link regarding 24hr biological clocks. A study regarding 48 hour cycles has also been reported

Other conditions
Dark Therapy has also been tried (in combination with bright light therapy, etc) for other conditions where seasonal exacerbation of symptoms in notable, such as nocturnal asthma, and associated depression, migraine, dyssomnia, chronic fatigue syndrome and fibromyalgia.

Melatonin secreted is preventative in cancer, and supportive of bone metabolism, immune function and detoxification.Melatonin has also been cited to reduce hypertension, produce better sleep for those with insomnia, and acts as an antioxidant.