Link to original: http://sphynxcatvp.nocturna.org/health/sc-non24.html
Unlike either Advanced Sleep Phase or Delayed Sleep Phase, Non-24 Sleep-Wake Disorder is a longer than average sleep-wake pattern, not just one that's offset from "normal". This article will explain more about Non-24 and why it's often harder to deal with than most people realize.
What is non-24 sleep-wake disorder?
Non-24 Sleep-Wake Disorder is a chronic circadian rhythm problem that is a steady pattern of 1-2 hour delays in sleeping and waking times each day. This pattern of delay goes around the clock and typically takes a few weeks to complete one cycle. Essentially, the body thinks the day is longer than 24 hours, sometimes as long as 28 hours, and doesn't reliably adjust to a regular 24-hr cycle.
This actually can be considered debilitating because a wandering wake/sleep cycle is NOT compatible with most social and/or professional obligations. Most cases reported in medical literature are patients who are totally blind (because of the body's lack of response to light.) It is considered rare in sighted individuals, with one theory being that it is a neurological problem, but some studies are finding that - like delayed sleep phase - it is actually not that uncommon in the teens and early 20's.
Though it is most often referred to as Non-24 Sleep-Wake Disorder, it is actually known by the following terms:
- Free running disorder (FRD)
- Hypernychthemeral syndrome
- Circadian rhythm sleep disorder free-running type
- Circadian rhythm sleep disorder nonentrained type
- Non-24-hour circadian rhythm disorder
- Non-24-hour sleep-wake disorder
What are the symptoms of non-24 sleep-wake disorder?
Page 139 of the ICSD 2001 (linked below) lists the symptoms of Non-24 Sleep-Wake as the following:
- The patient has a primary complaint of either difficulty initiating sleep or difficulty in awakening.
- Sleep onset and offset are progressively delayed, with the patient unable to maintain stable entrainment to a 24-hour sleep-wake pattern.
- The sleep pattern has been present for at least six weeks.
- Progressive sequential delay of the sleep period is demonstrated by one of the following methods:
- Polysomnography performed over several consecutive days on a fixed 24-hour bedtime and waketime schedule
- Continuous 24-hour temperature monitoring over at least five days that shows a progressive delay of the temperature nadir
- The symptoms do not meet the criteria for any other sleep disorder causing inability to initiate sleep or excessive sleepiness.
- Minimal Criteria: A plus B plus C.
Severity is graded by the degree of insomnia or sleepiness, with a corresponding impairment of social and/or professional functioning.
Unlike patients with delayed phase or advance phase sleep patterns, a patient with true non-24 does NOT have a stable (by the clock stable, that is) sleep-wake pattern even during lengthy vacations. Sometimes sleep may be skipped for 24-40 hours (or even longer) in an attempt to keep up with social and/or professional obligations, followed by sleeping for 14-24hours as the body attempts to catch up on sleep.
How is it diagnosed?
As with any really unusual medical condition - Non-24 being no exception to the rule - quite often the hardest part is getting a doctor to take you seriously in the first place!
A sleep log should be the first step, even if you can't get a doctor to take you seriously from the start. Track waking and sleeping times, the lighting conditions at sleeptime and wake time, the ambient lighting of the room, color of the lighting, food/drink every day, pain levels (if applicable) and anything else you can think of. If you believe that you have non-24, a sleep log may reveal a pattern you were previously unaware of, over the span of a few months - so even if you can't find a decent doctor, keep a sleep log anyway. If non-24 sleep-wake syndrome is present, it will be shown in a continued pattern of progressive days of sleep when there are no work/school/social obligations (such as vacation time.) If the patient is blind, this will be the first suspected diagnosis.
If the sleep log is inconclusive, a sleep study may be required, with possible neurological testing, especially in sighted individuals.
How is it treated?
There are the usual recommendations medical staff often recommend for dealing with this, and many other circadian rhythm problems:
Bright light therapy
This works by increasing the amount of natural sun exposure - or it's equivalent - in the morning and avoiding it late in the day. Specially designed "daylight bulbs" may be more useful to some if sun exposure isn't practical. These daylight bulbs can be acquired in various forms, such as a light box, a desk lamp, and even a visor that you wear.
This involves making the patient's bedtime earlier by 2-3 hours per day until the desired bedtime is reached. Once the desired time is reached, then the schedule should be rigorously maintained.
Improving sleep hygiene
Various sleep hygiene improvements will be suggested such as maintaining a regular sleep schedule - even on weekends, limiting activities for a few hours before bed that would keep the patient awake, making the sleep environment more comfortable, and avoiding caffeine and other chemical stimulants before bedtime.
(You can see some additional tips in my Insomnia article.)
Because melatonin plays a role in signaling the body to sleep, taking the supplement in the early evening may help some patients, depending on the timing.
The nature of Non-24 - especially the more severe varieties - makes any sort of treatment very problematic. Some self-help forums I viewed mention needing specific timing for melatonin, for example, stating that it simply could not be started "at any random point" in the sleep cycling. (I'm guessing it should be taken more when the body's sleep schedule has rotated around close to the desired timeframes.)
One blog I found - Sarlo, O., The Sandman is from Mars: Defeating the Non-24-Hr Sleep-Wake Syndrome - lists 15 steps the author took to set their Non-24 to a dayshift schedule, with an additional note that he has had no relapses for at least a year. The blog may be found linked below, but the steps - in decreasing order of importance - the author gives (and my explanatory notes) are as follows:
- Evening restriction of blue light: using yellow lamps and yellow tinted glasses.
- (Yellow lamps are a typically using the yellow "bug light" bulbs found in most hardware, discount and "Do It Yourself" stores. Blue light supresses the body's production of melatonin; so restriction of blue light should begin 3 hours before desired bedtime.)
- Using the "Relaxation Response" to relax and fall asleep (to shut down the cortex and avoid anxious thoughts).
- (This is basically a meditation process to slow the breathing and get the brain to calm down from the day's stresses.)
- Rising at the same time every day.
- (Use an alarm clock - or other extreme measures in the beginning of this process - if you need to.)
- Exposure to bright blue light upon waking.
- (A bunch of commonly available blue LED's will do the trick; the author uses them for about 30 minutes after he gets out of bed.)
- Going to bed at the same time every night.
- Sleeping in a light-proof room (pitch black).
- No arousing activities within an hour of bedtime.
- Using white-noise generators to screen-out abrupt sounds (e.g., leaving a box fan running in the background).
- No caffeine or alcohol after noon.
- Vigorous daily exercise.
- Eating a healthy balanced diet (natural foods).
- No sugary foods within three hours of bedtime.
- Finishing dinner at least 3 hours before bedtime.
- (Let the body finish digesting food; this should reduce some cases of heartburn as well.)
- Eating a larger number of smaller meals rather than few large ones.
- (It's hard to do anything - even sleep - when your stomach is too full and uncomfortable.)
- Adequate hydration, ceasing well before bedtime.
- (Just so your sleep doesn't get interrupted in the middle of the night by having to use the bathroom.)
True non-24 is considered to be uncommon in most adults - but this may also be due to medical staff discounting the possibility in anyone who brings it up. If you have non-24 and have gotten nowhere with the medical profession, it's worth giving the alternate treatment steps outlined above a try.
Heck, even if you don't have Non-24, but chronic insomnia due to another cause, these steps might still help.
Also remember, according to the - USA - Americans with Disabilities Act of 1990, "disability" is defined as a "physical or mental impairment that substantially limits one or more major life activities". "Sleeping" is defined as a "major life activity" in § 12102(2)(a) of the statute.
- American Academy of Sleep Medicine: ICSD Revised, 2001 Edition (PDF)
- Blog: The Sandman is from Mars: Defeating the Non-24-Hr Sleep-Wake Syndrome
- J Clin Endocrinol Metab. 2003 Sep: High sensitivity...to resetting by short wavelength light (PDF)
- PNAS.org: Entrainment of...human circadian pacemaker to longer-than-24-h... (PDF)
- PubMed: Circadian sleep regulation in the absence of light perception
- PubMed: Daily Melatonin Intake Resets Circadian Rhythms....
- PubMed: ...Effects of Low-Dose 0.5-mg Melatoning on Free-Running Circadian...
- PubMed: Melatonin in circadian sleep disorders in the blind
- PubMed: Non-24-Hour Sleep-Wake Syndrome in a Sighted Man...
- PubMed: Sensitivity of the human circadian system to short-wavelength (420-nm) light
- PubMed: A sighted man with non-24-hour sleep-wake syndrome...
- Sleep Medicine Reviews (2007) 11: Circadian rhythm sleep disorders... (PDF)
- Facebook Support Group: Non 24-Hour Sleep-Wake Syndrome Support Group