Delayed sleep phase syndrome
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Delayed sleep phase syndrome (DSPS) is a sleep disorder in which the patient's internal body clock is not in sync with the morning-rise evening-sleep pattern of the majority of adults. A growing body of evidence suggests that the problem is genetic, and may be inherited. DSPS patients may have a severely reduced reaction to the re-setting effect of daylight and even ordinary indoor lighting on the body clock.
The disorder can lead to harmful psychological and functional difficulties. It is often misdiagnosed and incorrectly treated due to the fact that doctors are unaware of the existence of DSPS.
Sufferers – traditionally termed "night owls" – have an identifiable sleep pattern, with the majority falling asleep in the pre-dawn hours and waking in the (early) afternoon. If sufferers are allowed to follow their in-built sleep pattern, there are generally no problems with either falling asleep or waking naturally.
However, left unacknowledged, DSPS can cause the same problems that would be expected if persons of the same age with normal sleep patterns should force themselves to wake up in the middle of the night and try to go to sleep too early in the evening.
For most sufferers, the problem is evident from infancy, though for some the onset is in adolescence. Parents may find themselves chastised for not giving their children acceptable sleep patterns, and schools are generally uncooperative in helping children. This can have severe physical and mental ramifications, as children are treated for insomnia and even ADHD or ADD when there is no real problem – except for the unsocial hour at which one is able to fall asleep.
Often, sufferers manage on a few hours sleep a night during the working week, then "catch up" by sleeping excessively at the weekend and sometimes by means of afternoon or evening naps, with inevitable effects on their social lives.
As many schoolchildren and young adults, particularly students, exhibit DSPS-like symptoms anyway (usually stemming from dislike of school, social activities and the like) initial diagnosis may be difficult.
Some consider a crucial test to be whether the patient is able to choose to wake up at normal times when it suits them – during holidays, for social outings etc. DSPS sufferers will usually find it as difficult to rise at 8 a.m. for a day out with friends as they will on a Monday morning. This is far from foolproof, however, as many DSPS sufferers will on occasion be able to rise early for short periods of time and may well be able to rise early for a social event that matters to them. They will just not be able to keep this up over a lengthy period of time. Unlike normal individuals, DSPS sufferers are not capable of 'advancing' their sleep cycles. Forcing the patient to go to sleep early with sleeping pills, etc. and regularly waking them early in the morning does not result in adaptation to the new sleeping pattern, but deprives them of necessary sleep.
DSPS is diagnosed by a clinical interview, actigraphic monitoring and/or a sleep log kept by the patient for at least three weeks.
Many sufferers deny the existence of any problem and refuse to accept that they may not be suited for a 9–5 lifestyle. This denial is often caused or exacerbated by friends and relatives claiming there is no such problem as DSPS and claiming the sufferer is "just lazy". Attempting to force oneself through 9–5 life with DSPS has been likened to "constantly living with 6 hours of jetlag".
Treatments include light therapy with a full spectrum lamp, usually 10000 lux for 30-90 minutes, and chronotherapy. These can have marked success with some patients. Treatment with melatonin taken an hour or more before bedtime may be helpful in establishing an earlier pattern, especially in conjunction with bright light therapy. Too high a dose of melatonin may have the unintended effect of disturbing the sleep or even causing nightmares and sleepiness the next day. The long-term effects of melatonin administration have not been examined and the treatment is not used in many countries because of this. Some claim that large doses of vitamin B12 help normalize the onset of sleepiness, but little is known of the effectiveness of the treatment. For some patients, acupuncture may be a solution; several treatments may be necessary before results, if any, are seen. Treatments do not effect a cure; they can only be a way to manage the condition. For many there is no cure, and social and work patterns must either be adjusted or the physical and mental penalties must be paid.
Several studies have shown that clinical depression is frequent in DSPS patients, possibly because of patients' inability to meet social demands.
Research into DSPS, and its opposite, ASPS, is only a couple of decades old and by no means conclusive. Many doctors reject its status as "incurable", while others see it as "shifted phase", i.e. that a normal pattern exists but has been suppressed. These beliefs are highly contentious, especially among sufferers.
There has been some confusion between DSPS and Non-24 hour sleep phase syndrome, in which the circadian rhythm has been extended, often to more than 27 hours. People with this syndrome will also typically sleep later than society deems normal. However, people with DSPS do, by definition, live on a 24 hour day. They can go to bed at the same time every morning and get up at the same time each day, be it 11 a.m. or 4 p.m. There have been some reports of DSPS 'developing into' non-24 hour syndrome.
Delayed sleep phase syndrome is commonly a part of autism.