Circadian rhythm sleep disturbances are characterized by a lack of synchronization between your internal sleep cycle and the normal social or environmental 24-hour clock. Advanced sleep phase syndrome, or ASPS, manifests as a need to go to sleep earlier in the evening than is desired, coupled with an earlier time of awakening. ASPS is more common among elderly individuals, and a September 1999 "Nature Medicine" article described an uncommon form of inherited advanced sleep phase syndrome.
Dim Light and Sleep
According to "The Merck Manual of Diagnosis and Therapy," light is the strongest single determinant of human circadian rhythms. During periods of dim light and darkness, the pineal gland at the base of your brain secretes a neurohormone called melatonin, which binds to receptors in your brain's sleep centers and helps to establish your circadian rhythm. Melatonin secretion is effectively abolished when you are in bright light.
Melatonin for Sleep
Taking oral melatonin to help re-establish normal sleep patterns has been useful for some circadian sleep disturbances, such as jet lag or shift-work sleep disorder. Doses of 0.5 to 5 mg are typically administered just before bedtime. However, in order to be effective, supplemental melatonin must be taken when you would normally secrete your own melatonin. Taking it at other times could actually aggravate your sleeping problems.
Advanced Sleep Phase Syndrome
Melatonin secreted from your pineal gland serves as your brain's signal for sleep. Thus, ASPS is characterized by the premature release of melatonin from your pineal gland. Taking extra melatonin at your established bedtime simply augments the effects of your own melatonin and makes you even sleepier. The treatment for ASPS entails delaying your internal clock, which can be accomplished by delaying the secretion of melatonin from your pineal gland.
Treatment
An August 2008 review published in "Annals of the Academy of Medicine, Singapore" describes an effective method for treating ASPS. Bright light therapy -- the type of device used to treat seasonal affective disorder is effective -- administered during the evening before your current bedtime effectively abolishes the premature release of melatonin from your pineal gland. Exposure to a 4,000 lux light for one to two hours before your current bedtime will delay your sleep cycle by up to two hours. Melatonin can then be taken at your new, delayed bedtime, if desired. Upon awakening, avoid bright light for a few hours to "solidify" the shift in your sleep cycle. Several days of therapy may be required.
Considerations
People with circadian rhythm sleep disturbances often do not have symptoms if they are allowed to adhere to their own schedule. It is the demands of work, school and social schedules that typically lead to excessive sleepiness, insomnia, irritability and even depression in such individuals. Light therapy alone or in combination with melatonin is often helpful for treating ASPS and other circadian rhythm sleep disorders.
References
- "Nature Medicine"; Familial Advanced Sleep-Phase Syndrome: A Short-Period Circadian Rhythm Variant in Humans; C.R. Jones, et al.; September 1999
- "The Merck Manual of Diagnosis and Therapy: Circadian Rhythm Sleep Disorders"; Mark H. Beers, M.D., Editor-in-Chief; 2006
- "Annals of the Academy of Medicine, Singapore"; Treatment of Circadian Rhythm Sleep Disorders with Light; J.J. Gooley; August 2008
