Circadian rhythms may play an important role in sufferers of rapid-cycling bipolar disorder - could darkness be the answer in tackling manic episodes?

Dark therapy is a fairly new chronobiological treatment involving exposure to darkness. Preliminary research has shown that this can be effective in treating manic episodes, particularly in sufferers of rapid-cycling bipolar disorder. Dark therapy is almost converse to the bright light therapy used for certain sleep disorders and depressive illnesses.

Rapid-Cycling Bipolar Disorder

Bipolar disorders are characterized by extreme mood swings of depression and mania. Rapid-cycling bipolar disorder (RCBP) is a specifier of bipolar disorder, rather than a separate illness. To be diagnosed, four or more episodes of mood swings must occur in a 12-month period.

Rapid-cycling can be very disruptive to a sufferer’s life, especially as it can be resistant to treatment such as lithium, a mood stabilizer often used to treat bipolar illnesses. The National Institute for Mental Health theorized that rapid-cycling may be linked to the body clock. Many sufferers of bipolar disorder complain of problems with sleep, and it’s notable that sleep deprivation may hasten the onset of mania.

Rapid-Cycling and the Body Clock

According to the American Psychiatric Association, researchers have been questioning the relationship between mood disorders and circadian rhythms for the last 60 years. These rhythms help the body to keep time, and are synchronized by the body clock. These rhythms may be unstable in sufferers with RCBD and it is thought that darkness may stabilize them.

The suprachiasmatic nucleus (SCN), or body clock, is located in the hypothalamus of the brain. The body clock regulates the pineal gland, which is responsible for secreting the sleep hormone melatonin. This hormone is produced in darkness. Light, specifically the blue wavelengths of light, impairs on the production of this hormone.

Dark Therapy Research

In 2005, a pilot study was conducted to see if enforced darkness could be helpful to people suffering manic episodes. Sixteen inpatients suffering with mania were treated with dark therapy, as well as their current mood stabilizers. This regimen involved a three-day treatment - 14 hours of darkness per day between 6pm and 8am.

The results were compared with a second group of patients (matched for age, sex and similar patterns of illness) who were not treated with dark therapy. The group treated with dark therapy showed significant improvement in mania symptoms, leaving hospital earlier and requiring lower doses of antimanic drugs. Other studies have since followed, showing similar results. More research is required to further explore the effects of dark therapy.

Disadvantages to Dark Therapy

Understandably, 14 hours of complete darkness is very inconvenient for sufferers. Although the sufferers sleep for eight of these hours, they are very limited in the activities they can partake in during the six hours they are awake. Fortunately, there may be a solution - virtual darkness.

Dark Therapy and Virtual Darkness

Another study monitored the effects of using amber glasses, with lenses designed to block out blue spectrum lights, thereby simulating darkness. As mentioned earlier, it is blue light that inhibits melatonin production, and so a blockade for blue light may have the same affect as complete darkness, but without the inconvenience, as sufferers who wear these glasses can still see.

Dark Therapy and Self-help

Dr Phelps of PsychEducation.org suggests a few self-help strategies that may help sufferers, using the underlying principles of dark therapy. It may be helpful to cut down on artificial light in the evenings, in particular TV and computers, which give out blue spectrum light. Avoiding staying up late and shift work may also be beneficial.

Read Living with Biplar Disorder for more information on self-management, therapy and medication. For more information on amber lenses and items that give off low blue light, you may wish to visit the Low Blue Lights website. Sufferers of bipolar disorder interested in this therapy may wish to ask their doctor or therapist for advice.

Sources

Dark therapy for mania: a pilot study: Bipolar Disorders, accessed 27th March 2008, authors - Barbini, B; Benedetti, F; Colombo, C; Dotoli, D; Bernasconi, A; Cigala-Fulgosi, M; Florita, M; Smeraldi, E

Dark therapy for bipolar disorder using amber lenses for blue light blockade: Medical Hypotheses, accessed 27th March 2008, author - Phelps, J