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Sleep Disorders

Inability to sleep at night



Hi! My brother (who`s 21 years old) can`t sleep at night at all. He doesn`t fall asleep untill about 4/6 o`clock in the morning and the results are that he doesn`t wake up untill late afternoon (sometimes as late as 4 o`clock). I heard of a sleeping disorder called Non-24-Hour-Sleep-Sake Syndrome but I couldn`t find any information about it. Can you help me understand why he can`t sleep and suggest any treatment , preferably not medication as he´`s unwilling to take any.

Yours Sincerely.


This really sounds like your brother has a delayed sleep phase and not Non-24 hour Sleep-Wake Syndrome. In Non-24 hour Sleep-Wake Syndrome, the internal body clock tends to run longer than 24 hours and, in a the absence of appropriate timing cues (light exposure, meals, etc.), the individuals day runs longer than 24 hours and so they tend to go to sleep later and later each day until they literally have slept around the clock. This condition is relatively uncommon and seen almost exclusively in blind individuals.

Delayed sleep phase syndrome is much more common and likely what your brother has. Our internal body clocks play a major role in determining when we feel sleepy and when we feel awake. For most individuals, the circadian rhythms (or biorhythms that control the internal clock) are in line with the usual day-night schedule and they have no trouble sleeping at night and staying awake during the daytime. However, in some individuals, there appears to be underlying genetic influences that favor staying up late and sleeping in late into the daytime (these are the so called "night owls").

Likewise, others appear to be genetically engineered to do just the opposite; they have a tendency to go to fall asleep early in the evening and then awaken early in the morning (these are the so called "morning larks"). Your brother appears to fit into the first category and has what is known as a delayed sleep phase. A delayed sleep phase is not uncommon amongst teenagers and young adults. Adolescents often like to stay up late and sleep in, especially on the weekends. When this becomes their regular sleep habit every night of the week, problems may develop. Individuals who like to stay up late at night need to be able to sleep late in order to get enough sleep. However, when they are required to awaken early for school or work, they tend to not get enough sleep. This type of sleep pattern fits the diagnosis of delayed sleep phase syndrome and is quite common in adolescents and young adults (about 10 times more common than in middle-aged adults). The lack of sleep that results may contribute to daytime sleepiness and poor performance at school or work.

This is being increasingly recognized in society as a problem and some states are now experimenting with a later start time for high school students to see if this will impact behavior and performance. Delayed sleep phase syndrome can usually be treated with behavioral modification and measures to help change the individual's circadian rhythm cycle, which determine when an individual becomes sleepy. The body's circadian rhythms usually cycle over a 24 to 25 hour time period. These rhythms are reset daily to match a 24 hour day by factors such as exposure to daylight and social cues, for example when we eat our meals. The internal clock can be advanced (moved forward so you are sleepy earlier in the evening) or delayed (moved backwards so you are more awake late into the night) by changing the timing of light exposure and other social cues. However, the internal clock can only be adjusted by 1-2 hours in either direction per day with these maneuvers. When individuals try to alter their rhythms by more than this, they tend to feel poorly with fatigue, sleepiness and nausea (as seen with Jet Lag, for example). Furthermore, it often takes several days to fully adjust our circadian rhythms to a new schedule.

The most powerful tools available to shift the sleep pattern forward (or to "advance" sleep) are light exposure and melatonin. Light exposure has the strongest effect on the circadian cycle and timing of light exposure is crucial for individuals with circadian rhythm disorders. For delayed sleep phase syndrome, early day light exposure (usually between 6 and 9 AM), while avoiding bright light late in the day, can advance the sleep schedule. However, for this to be effective, enough bright light for a long enough time period is usually required (this is often accomplished with the use of a "light box" that can deliver 10,000 lux for 30 minutes or 2500 lux for 2 hours, though the optimal dose and length of exposure are not clearly known). In the summer time, early morning sunlight exposure works just fine. Strictly adhering to the treatment regimen is vital to ensure success for this therapy. Melatonin, which is naturally produced by the brain in response to darkness, helps to promote sleep.

For those with delayed sleep phase syndrome, use of this drug may help to advance the sleep phase. However, caution must be advised as this drug is sold as an over the counter supplement and is not FDA regulated. Therefore, there is no guarantee with regards to the purity of the product and this may place an individual at risk for unpredictable side effects. Recently, a prescription melatonin-like drug has become available (ramelteon), though this has not yet been studied in humans for use in circadian rhythm disorders. Other tools that can help to shift the sleep phase include timing of meals (avoiding late meals), pre-bedtime rituals (avoiding stimulating activities) and avoiding medications or substances (for example caffeine and nicotine) with stimulating side effects near bedtime. Daytime stimulant therapy is not typically recommended for delayed sleep phase syndrome as the above measures, when adhered to, are often quite effective. Likewise, sleeping pills such as tranquilizers tend to be less effective without some changes in the underlying circadian rhythms.

Another technique that can work for some individuals with delayed sleep phase syndrome is to "sleep through the clock." This requires a person to have no other daytime commitments and to adhere to a strict sleep schedule. The idea here is to delay the sleep schedule by 2 hours a day (gradually moving bedtime back through the day) until the individual reaches their desired bedtime, whereupon they maintain a regular sleep schedule at that time thereafter. This approach can be difficult and requires close supervision, usually by a Sleep Specialist, in addition to a very flexible and motivated patient.

If, after making the above adjustments, your brother is still having problems, he should probably speak to his doctor. Referral to a Sleep Specialist may be needed to determine the exact nature of the problem and how best to manage it.

If you would like further information about sleep and sleep disorders, I recommend the American Academy of Sleep Medicine website. In addition to information about sleep medicine, the website also contains a list of accredited Sleep Centers and may help you to locate one nearest you. The website Sleep Education.com also provides plenty of good consumer friendly information. Good Luck!

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Response by:

Dennis   Auckley, MD Dennis Auckley, MD
Associate Professor of Medicine
School of Medicine
Case Western Reserve University