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'''Delayed sleep-phase syndrome''' ('''DSPS''') is a chronic [[circadian rhythm sleep disorder|disorder of sleep timing]]. People with DSPS tend to fall asleep at very late times, and also have difficulty waking up in time for normal work, school, or social needs.
'''Delayed sleep-phase syndrome''' ('''DSPS''') is a chronic [[circadian rhythm sleep disorder|disorder of sleep timing]]. People with DSPS tend to fall asleep at very late times, and also have difficulty waking up in time for school or work that begins in the morning.


Often, DSP individuals report that they cannot sleep until early morning. Unlike [[Insomnia|insomniacs]], however, they fall asleep at about the same time every night, no matter what time they go to bed. Unless they have another sleep disorder such as [[sleep apnea]] in addition to DSPS, patients can sleep well, and have a normal need for sleep. Therefore, they find it very difficult to wake up in the morning if they have only slept for a few hours. However, they sleep soundly, wake up spontaneously, and do not feel sleepy again until their next "night," if they are allowed to follow their own late schedule, e.g. sleeping from 4 am to noon.
Often, DSP individuals report that they cannot sleep until early morning. Unlike [[Insomnia|insomniacs]], however, they fall asleep at about the same time every night, no matter what time they go to bed. Unless they have another sleep disorder such as [[sleep apnea]] in addition to DSPS, patients can sleep well, and have a normal need for sleep. Therefore, they find it very difficult to wake up in the morning if they have only slept for a few hours. However, they sleep soundly, wake up spontaneously, and do not feel sleepy again until their next "night," if they are allowed to follow their own late schedule, e.g. sleeping from 4 am to noon.
Line 107: Line 107:
Dagan, Yaron and Abadi, Judith Sleep-Wake Schedule Disorder Disability: A lifelong untreatable pathology of the circadian time structure. ''Chronobiology International'' 2001; Volume 18, Number 6 Pages: 1019 - 1027</ref>}}
Dagan, Yaron and Abadi, Judith Sleep-Wake Schedule Disorder Disability: A lifelong untreatable pathology of the circadian time structure. ''Chronobiology International'' 2001; Volume 18, Number 6 Pages: 1019 - 1027</ref>}}


Rehabilitation for DSPS patients includes [[acceptance]] of the condition, and choosing a career that allows late sleeping times. Some DSPS-friendly careers include computer programming, work in theatre, freelance writing, and taxi or truck driving.
Rehabilitation for DSPS patients includes [[acceptance]] of the condition, and choosing a career that allows late sleeping times. Some DSPS-friendly careers include computer programming, work in theatre, the media, freelance writing, and taxi or truck driving.


== DSPS and depression ==
== DSPS and depression ==

Revision as of 16:57, 25 October 2006

Delayed sleep phase disorder
SpecialtyNeurology Edit this on Wikidata

Delayed sleep-phase syndrome (DSPS) is a chronic disorder of sleep timing. People with DSPS tend to fall asleep at very late times, and also have difficulty waking up in time for school or work that begins in the morning.

Often, DSP individuals report that they cannot sleep until early morning. Unlike insomniacs, however, they fall asleep at about the same time every night, no matter what time they go to bed. Unless they have another sleep disorder such as sleep apnea in addition to DSPS, patients can sleep well, and have a normal need for sleep. Therefore, they find it very difficult to wake up in the morning if they have only slept for a few hours. However, they sleep soundly, wake up spontaneously, and do not feel sleepy again until their next "night," if they are allowed to follow their own late schedule, e.g. sleeping from 4 am to noon.

DSPS usually develops in adolescence or early childhood[1], and sometimes disappears in adolescence or early adulthood. It is usually treatable, but cannot be cured.

DSPS was first formally described in 1981 by Dr. Elliot D. Weitzman and others at Montefiore Medical Center.[2] It is responsible for 7 -10% of cases of chronic insomnia.[3]. However, as few doctors are aware of its existence, it often goes untreated or is treated inappropriately.


Definition

According to the International Classification of Sleep Disorders (ICSD), the key characteristics of DSPS are:

  1. Sleep-onset and wake times that are intractably later than desired
  2. Actual sleep-onset times at nearly the same daily clock hour
  3. Little or no reported difficulty in maintaining sleep once sleep has begun
  4. Extreme difficulty awakening at the desired time in the morning
  5. A relatively severe to absolute inability to advance the sleep phase to earlier hours by enforcing conventional sleep and wake times.[4]

The following features of DSPS distinguish it from other sleep disorders:

  • People with DSPS have at least a normal - and often much greater than normal - ability to sleep during the morning, and sometimes in the afternoon as well. In contrast, those with chronic insomnia do not find it much easier to sleep during the morning than at night.
  • People with DSPS fall asleep at more or less the same time every night, and sleep comes quite rapidly if the person goes to bed near the time he or she usually falls asleep. Young children with DSPS resist going to bed before they are sleepy, but the bedtime struggles disappear if they are allowed to stay up until the time they usually fall asleep.
  • DSPS patients can sleep well and regularly when they can follow their own sleep schedule, e.g. on weekends and during vacations.
  • DSPS is a chronic condition. A diagnosis of DSPS is generally not given unless symptoms have been present for at least a month.

Attempting to force oneself through 9–5 life with DSPS has been compared to constantly living with 6 hours of jet lag. Often, sufferers manage only a few hours sleep a night during the working week, then compensate by sleeping until the afternoon on weekends. Sleeping in on weekends, and/or taking long naps during the day, gives the DSPS patient relief from daytime sleepiness but also perpetuates the late sleep phase.

People with DSPS tend to be extreme night owls. They feel most alert and say they function best and are most creative in the evening and at night. DSPS patients cannot simply force themselves to sleep early. They may toss and turn for hours in bed.

By the time DSPS patients seek medical help, they usually have tried many times to change their sleeping schedule. Failed tactics to sleep at earlier times may include relaxation techniques, early bedtimes, hypnosis, alcohol, sleeping pills, dull reading, and home remedies. DSPS patients who have tried using sedatives at night often report that the medication makes them feel tired or relaxed, but that it fails to induce sleep. They often have asked family members to help wake them in the morning, or they have used several alarm clocks. Or family members - especially parents - have tried to get them up on time.

Prevalence

Using the strict ICSD diagnostic criteria, a random study of 10,000 adults in Norway estimated the prevalence of DSPS at 0.17%. [5]. A similar study with 1525 adults in Japan estimated its prevalence at 0.13%. [6]. Other studies have indicated that the prevalence of DSPS among adolescents is as high as 7%.

Physiology

Main article: Circadian rhythm sleep disorder

DSPS is a disorder of the body's timing system - the biological clock. It is believed to be caused by a reduced ability to reset the body's daily sleep/wake clock. Individuals with DSPS might have an unusually long circadian cycle, or might have a reduced response to the re-setting effect of light on the body clock.

People with normal circadian systems can generally fall asleep quickly at night if they did not have enough sleep the night before. Falling asleep earlier will in turn automatically advance their circadian clocks. In contrast, people with DSPS are unable to fall asleep before their usual sleep time, even if they are sleep-deprived. Research has shown that sleep deprivation does not reset the circadian clock of DSPS patients, as it does with normal people.[7]

DSPS patients who try to live on a normal schedule have difficulty falling asleep and difficulty waking because their biological clocks are not in phase with that schedule. Normal people who do not adjust well to working a night shift have similar symptoms.

People with DSPS show delays in other circadian markers, such as melatonin-secretion and core body temperature minimum, that correspond to the delay in the sleep/wake cycle. Sleepiness, spontaneous awakening, and these internal markers are all delayed by the same number of hours. Non-dipping blood pressure patterns are also associated with DSPS when present in conjunction with socially unacceptable sleeping and waking times.

In most cases, it is not known what causes the abnormality in the biological clocks of DSPS patients. DSPS tends to run in families[8] and a growing body of evidence suggests that the problem is associated with the hPer3 (human period 3) gene. [9] There have been several documented cases of DSPS and non-24 hour sleep-wake syndrome developing after traumatic head injury. [10] [11].

There have been a few cases of DSPS developing into non 24-hour sleep-wake syndrome, a more severe and debilitating disorder in which the individual sleeps later each day.

Diagnosis

DSPS is diagnosed by a clinical interview, actigraphic monitoring and/or a sleep log kept by the patient for at least three weeks.

DSPS is frequently misdiagnosed or dismissed. It has been named as one of the sleep disorders most commonly misdiagnosed as a primary psychiatric disorder [12]. DSPS is often confused with psychophysiological insomnia, depression, psychiatric disorders such as schizophrenia, ADHD or ADD, other sleep disorders, or willful behaviour such as school refusal. Practitioners of sleep medicine point out the dismally low rate of accurate DSPS diagnosis, and have often asked for better physician education on sleep disorders. [13].

Impact on patients

Lack of public awareness of the disorder contributes to the difficulties experienced by DSPS patients, who are commonly stereotyped as undisciplined or lazy. Parents may be chastised for not giving their children acceptable sleep patterns, and schools rarely tolerate chronically late, absent, or sleepy students.

At a 2004 World Health Organization meeting on the effects of sleep on health, sleep experts noted that:

medium and long term effects... are known especially in DSPS. Affected individuals suffer from chronic sleep deprivation and from behavioral and cognitive consequences of sleep debt. There is increased abuse of alcohol and other substances, and some young subjects show criminal leanings. A striking relationship has been found between circadian rhythms and psychiatric disorders, particularly seasonal affective disorder, primary depression, and bipolar affective disorder.[14].

By the time DSPS sufferers receive an accurate diagnosis, they often have been misdiagnosed or labelled as lazy for years. Misdiagnosis of circadian rhythm sleep disorders as psychiatric conditions causes considerable distress to patients and their families, and leads to some patients being inappropriately prescribed psychoactive drugs. For many patients, diagnosis of DSPS is itself a life-changing breakthrough.[15]

Treatment

Treatment for DSPS is specific. It is different from treatment of insomnia, and recognizes the patient's ability to sleep well while addressing the timing problem.

Mild cases of DSPS can be controlled by waking up and going to bed 15 minutes earlier every day until the desired sleep schedule is reached. More severe cases are treated by the methods discussed below.

Before starting DSPS treatment, patients are often asked to spend a week sleeping regularly, without napping, at the times when the patient is most comfortable. It is important to start treatment well-rested.

Treatments that have been reported in the medical literature include:

  • Light therapy (phototherapy) with a full spectrum lamp or portable visor, usually 10000 lux for 30-90 minutes in the morning. Avoidance of bright light in the evening may also help.
  • Chronotherapy, which consists of resetting the circadian clock by going to bed several hours later each day for several days.
  • A small (~1mg) melatonin supplement taken an hour or so before bedtime may be helpful in establishing an earlier pattern, especially in conjunction with bright light therapy at the time of spontaneous awakening. Side effects of melatonin may include disturbance of sleep, daytime sleepiness and depression. The long-term effects of melatonin administration have not been examined and production is unregulated. In some countries the hormone is available only by prescription or not at all.
  • Some claim that large doses of vitamin B12 help normalize the onset of sleepiness, but little is known of the effectiveness of the treatment.
  • A treatment option which shows promise is Ramelteon, a recently-approved drug which in some ways acts as a synthetic melatonin. Production of ramelteon is as regulated as any other prescription medicine, so it avoids the problems of variable purity and dosage with melatonin supplements.
  • Modafinil is approved in the USA for treatment of Shift-work sleep disorder, which shares some characteristics with DSPS, and a number of clinicians are prescribing it for DSPS patients.
  • There has been one documented case in which a person with DSPS was successfully treated with trazodone. [16]

Once the patient has established an earlier sleep schedule, following highly regular sleep/wake times and practicing good sleep hygiene are essential.

See Also: Phase response curve

Prognosis

Long-term success rates of treatment have not been evaluated, however experienced clinicians acknowledge that DSPS is difficult to treat.

Some people with DSPS are unable to adapt to earlier sleeping times, even after many years of treatment. Sleep researchers have proposed that the existence of untreatable cases of DSPS be formally recognized as a "sleep-wake schedule disorder disability" (SWSD).

Patients suffering from SWSD disability should be encouraged to accept the fact that they suffer from a permanent disability, and that their quality of life can only be improved if they are willing to undergo rehabilitation. It is imperative that physicians recognize the medical condition of SWSD disability in their patients and bring it to the notice of the public institutions responsible for vocational and social rehabilitation.[15]

Rehabilitation for DSPS patients includes acceptance of the condition, and choosing a career that allows late sleeping times. Some DSPS-friendly careers include computer programming, work in theatre, the media, freelance writing, and taxi or truck driving.

DSPS and depression

In the DSPS cases reported in the literature, about half of the patients have suffered from clinical depression or other psychological problems. The relationship between DSPS and depression is unclear. The fact that some DSPS patients are not depressed indicates that DSPS is not merely a symptom of depression. Even in depressed patients, treatment methods such as chronotherapy can be effective without directly treating the depression.

It is conceivable that DSPS often has a major role in causing depression, because it can be such a stressful and misunderstood disorder. A direct neurochemical relationship between sleep mechanisms and depression is another possiblity.

DSPS patients who also suffer from depression should seek treatment for both problems. There is some evidence that effectively treating DSPS can improve the patient's mood and make antidepressants more effective. In addition, treatment for depression can make patients more able to successfully follow DSPS treatments.

  • In one Calvin and Hobbes comic strip, Calvin says as he is woken up, "No! No! No! I need more sleep!" He can hardly keep his eyes open in school that day, but while being dragged upstairs that evening by his mother, screams, "Bed?! Already?? But I'm wide awake!" In the last panel of the strip, Calvin says, "My internal clock is on Tokyo time."

See also

Notes

  1. ^ Dagan Y; Eisenstein M Circadian rhythm sleep disorders: toward a more precise definition and diagnosis. Chronobiol Int 1999 Mar;16(2):213-22
  2. ^ *Weitzman, E.D., Czeisler, CA; et al. (1981). "Delayed sleep phase syndrome: a chronobiological disorder with sleep-onset insomnia". Archives of General Psychiatry. 38: 737–746. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  3. ^ "Sleeplessness and Circadian Rhythm Disorder". eMedicine World Medical Library from WebMD. Retrieved 2006-06-04.
  4. ^ American Academy of Sleep Medicine International Classification of Sleep Disorders, Revised Edition 2001.
  5. ^ Schrader H, Bovim G, Sand T. The prevalence of delayed and advanced sleep phase syndromes. J Sleep Res. 1993 Mar;2(1):51-55.
  6. ^ Yazaki, Mikako et al. Demography of sleep disturbances associated with circadian rhythm disorders in Japan Psychiatry and Clinical Neurosciences Volume 53 Issue 2 Page 267 April 1999
  7. ^ Uchiyama, Makoto et al. Poor recovery sleep after sleep deprivation in delayed sleep phase syndrome Psychiatry and Clinical Neurosciences Volume 53 Issue 2 Page 195 - 197 April 1999
  8. ^ Ancoli-Israel S, Schnierow B, Kelsoe J, Fink R. (2001). "A pedigree of one family with delayed sleep phase syndrome". Chronobiology International. 18 (5): 831–840.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ Evolution of a length polymorphism in the human PER3 Gene, Nadakarni et al.JOURNAL OF BIOLOGICAL RHYTHMS / December 2005.
  10. ^ Boivin, D.B. et al. Non-24-hour sleep–wake syndrome following a car accident Neurology 2003;60:1841-1843
  11. ^ Quinto, Christine et al. Posttraumatic delayed sleep phase syndrome Neurology 2000;54:250
  12. ^ Stores, Gregory. Misdiagnosing sleep disorders as primary psychiatric conditions. Advances in Psychiatric Treatment 2003, vol.9, 69-77
  13. ^ Dagan, Yaron M.D., D.Sc.; Ayalon, Liat Ph.D. Case Study: Psychiatric Misdiagnosis of Non-24-Hours Sleep-Wake Schedule Disorder Resolved by Melatonin. Journal of the American Academy of Child & Adolescent Psychiatry. December 2005;44(12):1271-1275.
  14. ^ WHO Technical meeting on sleep and health - meeting report, accessed August 12 2006
  15. ^ a b Dagan, Yaron and Abadi, Judith Sleep-Wake Schedule Disorder Disability: A lifelong untreatable pathology of the circadian time structure. Chronobiology International 2001; Volume 18, Number 6 Pages: 1019 - 1027
  16. ^ Nakasei, Shinji et al. Trazodone advanced a delayed sleep phase of an elderly male: A case report Sleep and Biological Rhythms Volume 3 Page 169 - October 2005

References

  • Thorpy, M.J.; et al. (1988). "Delayed sleep phase syndrome in adolescents". Journal of Adolescent Health Care. 9: 22–27. {{cite journal}}: Explicit use of et al. in: |author= (help)
  • "When the body clock goes wrong: delayed sleep phase syndrome". Lancet. 340: 884. 1992.
  • Regestein, Q.; et al. (1995). "Treatment of delayed sleep phase syndrome". General Hospital Psychiatry. 17: 335–345. {{cite journal}}: Explicit use of et al. in: |author= (help)
  • Regestein, Q. and Monk, TH (1995). "Delayed sleep phase syndrome: a review of its clinical aspects". American Journal of Psychiatry. 152: 602–608.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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