Delayed Sleep Phase Disorder

 

 

Sleep Disorders Traced to Genes

by Randy Dotinga

If you like to go to sleep after Conan O'Brien or wake up shortly before lunch, you may have your ancestors to blame.

Researchers at two American universities suspect that night owls inherit their sleep patterns, and they're launching a study that could lead to new gene therapy for everyone from insomniacs to early birds who can't help but hit the sack before prime time.

It may be years, even decades, before gene-based drugs compete with the traditional insomnia remedies of sleeping pills, warm milk or hot toddies.

Researchers only began to seriously explore the genetics of sleep in the mid-1990s, and they're far from determining which genes are in charge of the body clock. Even so, there appears to be a general consensus that many of us don't voluntarily choose to be short sleepers or long sleepers, morning people or night people.

"For some time now, doctors who see people with sleep disorders have been documenting a familial relationship in these things. That's commonly the first way that people start thinking about a particular disease as being genetic, by seeing it cluster in families," said Dr. Walt Klimecki, a geneticist at the University of Arizona who is working with sleep researchers at the University of California at San Diego.
Indeed, researchers have discovered that some people seem to inherit a pesky early-to-sleep/early-to-rise syndrome. A notorious sleep disease -- the rare fatal familial insomnia, which robs people of sleep until they die from lack of it -- also runs in families.

Researchers at UCSD are recruiting Southern California night owls to undergo monitoring and genetic testing to see if their condition is inherited too. The participants have a condition called delayed sleep-phase syndrome and typically prefer to go to bed in the early hours of the morning and wake up after 9 or 10 a.m., when many people are already caffeinated and ready for work.

This sort of behavior won't sound unusual to countless college students or teenagers. But in the most severe cases of the syndrome, simply trying to go to bed earlier doesn't work, according to UCSD sleep researcher Dr. Dan Kripke.

"Some people are quite disabled by delayed sleep phase if their school work or employment requires them to get up early," he said. "They could voluntarily get up in the middle of their sleep period, but after a few days, they become so sleep-deprived, they can't continue to do it for the long run."
Perhaps 1 percent of the population has the disorder, Kripke said.
For reasons that aren't clear, it's much rarer for people to have the opposite condition -- advanced sleep-phase syndrome -- and be unable to postpone sleep past 7 or 8 p.m. Researchers elsewhere have already identified at least one of the genes that appear to cause that problem.

Extremely bright light boxes, which try to reset our internal clocks by making our bodies think it's morning, are a common treatment for sleep-phase disorders. Some patients take melatonin, a signaling hormone that can manipulate the body clock by tricking it into thinking it's dark and time for bed.
The University of Arizona's Klimecki suspects that, as in so many other medical conditions, sleep problems appear when genetics interact with other factors. Just as in illnesses like asthma, genetic predispositions don't necessarily doom someone to an unusual sleep pattern. Years ago, "we used to think of all these diseases as purely genetic," he said. "But now, we're realizing that the environment is really important as well."

Evolution could conceivably play a role too. Natural selection frequently affects both the development of diseases and resistance to them. For instance, an inherited trait that protected people from smallpox in the Middle Ages also appears to keep their descendents from getting AIDS. Klimecki pointed out that some blood disorders may have survived over time because they kept people from getting malaria.

But many more ailments appear to have developed independently from the pressures of evolution, and sleep problems may be among them, Klimecki said.

Once researchers figure out which genes affect sleep, they'll try to understand exactly how they affect the mysterious body clock, which typically resets itself after about 24 hours, and starts our daily cycles -- eating, sleeping and so on -- once again. Hence the term "circadian rhythm" -- "circadian" means "about a day."

Gene research in humans will also provide insight into the daily rhythms of animals.

"Nature uses the same genes and the same code to create the (body) clock in human beings as it does to create the clock in fruit flies," said Dr. Gregory Belenky, director of the Sleep and Performance Research Center at Washington State University at Spokane.

But body clocks aren't independent timekeepers: They depend on sunlight and darkness. In people who are kept away from the cues of light and dark, such as blind people, body clocks often boost the period of a "day" slightly beyond 24 hours, said Dr. Al Lewy, a sleep researcher at Oregon Health and Science University. In such people, the right time to go to sleep runs later and later each night, causing major disruptions to their lives. For the blind, who are immune to the effects of light boxes, melatonin may be the only treatment.

If researchers do get a handle on the genetics of sleep and the body clock, they may do more than produce gene-based treatments. According to Belenky, doctors could test people like pilots and special armed forces units to determine how they would handle sleep deprivation.

The tests might even give the lie to people who like to think they can easily skip sleep when they're actually not built to miss snooze time.

"People tend to think, 'Oh well, I'd like to get eight (hours), but I can manage with six,'" Belenky said. "But that's not true."


 

From yee Wiki:

Delayed sleep-phase disorder (DSPD), also known as delayed sleep-phase syndrome (DSPS) or delayed sleep-phase type (DSPT), is a circadian rhythm sleep disorder affecting the timing of sleep, peak period of alertness, the core body temperature rhythm, hormonal and other daily rhythms, compared to the general population and relative to societal requirements. People with DSPD generally fall asleep some hours after midnight and have difficulty waking up in the morning.

Affected people often report that while they do not get to sleep until the early morning, they do fall asleep around the same time every day. Unless they have another sleep disorder such as sleep apnea in addition to DSPD, patients can sleep well and have a normal need for sleep. However, they find it very difficult to wake up in time for a typical school or work day. If, however, they are allowed to follow their own schedules, e.g. sleeping from 4 a.m. to noon (04:00 to 12:00), they sleep soundly, awaken spontaneously, and do not experience excessive daytime sleepiness.

The syndrome usually develops in early childhood or adolescence. An adolescent version disappears in adolescence or early adulthood; otherwise DSPD is a lifelong condition. Depending on the severity, the symptoms can be managed to a greater or lesser degree, but there is no all-encompassing cure. Prevalence among adults, equally distributed among women and men, is approximately 0.15%, or 3 in 2,000. It is also genetically linked to ADHD by findings of polymorphism in genes in common between those apparently involved in ADHD and those involved in the circadian rhythm and a high proportion of DSPD among those with ADHD.


DSPD was first formally described in 1981 by Dr. Elliot D. Weitzman and others at Montefiore Medical Center. It is responsible for 7–10% of patient complaints of chronic insomnia. However, as few doctors are aware of it, it often goes untreated or is treated inappropriately; DSPD is often misdiagnosed as primary insomnia or as a psychiatric condition. DSPD can be treated or helped in some cases by careful daily sleep practices, light therapy, and medications such as melatonin and modafinil (Provigil). The former is a natural neurohormone responsible partly and in tiny amounts for the human body clock. At its most severe and inflexible, DSPD is a disability.

For more, go to:
http://en.wikipedia.org/wiki/Delayed_sleep_phase_disorder

In the News: Using iPads before bed 'can lead to a poor night's sleep'




Using tablets like the iPad or Galaxy Note late at night can inhibit sleep, according to research. Photo: ALAMY

 




Using tablet computers like Apple’s iPad and Samsung’s Galaxy Note just before bed can lead to a poor night’s sleep, according to research.

by Stephen Adams, The Telegraph Medical Correspondent

Sep 10, 2012

More and more people are taking their tablets to bed with them to surf the web, check Facebook or email before switching off the light.

But researchers are warning that the blueish light their screens emit can stop users getting a good night’s sleep.

That is because this type of light mimics daylight, convincing the brain that it is still daytime.

Blue light suppresses production of a brain chemical called melatonin, which helps us fall sleep. This is because our brains have evolved to be wakeful during daylight hours.

By contrast, light which is more orange or red in tone does not suppress melatonin production, perhaps because our brains recognise it as a cue that the day is ending.

Neurologists have known for years that staring at screens late in the evening can disrupt sleep - be they television screens, computer screens or mobile phone screens.

However, because mobiles and tablets are by nature portable - not to say addictive - more people are taking them into the bedroom.

Users also tend to hold them much closer to their eyes than a computer or television screen.
Researchers at the Lighting Research Centre, at the Rensselaer Polytechnic Institute in New York, are warning that looking at tablet displays for more than two hours “leads to a suppression of our natural melatonin levels as the devices emit optical radiation at short wavelengths” - in other words, they emit bluer light.

They say: “Although turning off devices at night is the ultimate solution, it is recommended that if these devices are used at night displays are dimmed as much as possible and that the time spent on them before bed should be limited.”

They drew their concludions after measuring melatonin levels in 13 volunteers, after they had spent time viewing iPads at full brightness at a distance of 10 inches, for two hours.
Melatonin levels were significantly lower after they had done this, than they were after the volunteers had viewed their iPads for the same time, but while wearing orange glass goggles, which cut out the blue light.

They wrote in the journal Applied Ergonomics that tablet makers could "tune the spectral power distribution of self-luminous devices" so that they disrupted the sleep patterns of users less.

It is not just a good night’s sleep that could be jeopardised by too much late night screen time.
Researchers know that persistent disruption to sleep patterns can lead to an increased risk of obesity, and even breast cancer.

However, these studies tend to be comparisons of those with chronic sleep disruption, such as long term shift workers, with those who have normal sleep patterns.

What Is the Ideal Time To Go To Bed?

by Jason Thibodeau, Software developer, science geek

  Studies on circadian rhythms suggest that sleeping 10 PM to 6 AM will give the most returns. This considers not only when the body appears to be the most geared for sleep, but also when the body is ready for other activities in the day.

For example, it appears we are most alert around 10 AM. It has been suggested that this time is ideal for performing your most challenging tasks of the day. The late afternoon appears ideal for physical exercise. Being awake and rested, and on a schedule, can help you take advantage of your highs and lows throughout the day.

Studies of the health impacts of working night shift have shown various negative factors, including higher risks of developing chronic health problems. A well known 2001 study suggested that women who worked graveyard shift had a significantly higher risk for developing breast cancer, due to exposure to light, suppressing the normal nocturnal release of melatonin, which in turn has an impact on estrogen release.

http://jnci.oxfordjournals.org/c...

A BBC Horizon episode "The Secret Life of your Body Clock" attempts to answer the question of what we should be doing at what times of the day, in regards to our internal "body clock."

http://www.bbc.co.uk/programmes/...
(The complete episode may be found on Youtube. Search: "BBC Horizon body clock")

http://en.wikipedia.org/wiki/Cir...

Morning larks and night owls

The majority of people appear to be "morning larks," who optimally would sleep at 10 PM and rise at 6 AM. However, it is estimated that 10-20% of the population are what are referred to as "night owls," people who are more mentally alert later in the day. Night owls are reported to be "less happy" than morning larks, often waking with a scowl in early hours.

By age 60, most people are morning types, the researchers found. Only about seven percent of young adults are morning larks, but as the population ages, this switches -- in the older years only about seven percent of the population are still night owls.

Since light exposure appears to be the trigger for many of our biological processes, this article suggests a regular waking time and exposure to natural light in the early morning could help "convert" a night owl into a morning lark. The reason for the difference is not known.

http://news.discovery.com/human/...

Further reading on delayed sleep phase syndrome:

http://en.wikipedia.org/wiki/Del...

Forbes: How To Reset Your Inner Clock To Get Quality Sleep

by Susan Adams, Forbes staff

We get lots of books sent to us here on the Forbes leadership team. My colleague Fred Allen and I were especially intrigued by a new volume that professes to have an elixir for insomnia, depression, fatigue and other sleep-related problems. I’m a lifelong insomniac and Fred says he tends to get sleepy every night directly after dinner. We wondered if this book might have solutions for our endless struggles.

The book is called Chronotherapy: Resetting Your Inner Clock To Boost Mood, Alertness, and Quality Sleep, and it’s written by two Ph.D.s, Michael Terman, the director of the Center for Light Treatment and Biological Rhythms at Columbia University Medical Center, and Ian McMahan, of the City University of New York. According to Terman and McMahan, humans have a great deal of sensitivity to the timing and brightness of light exposure. Those mechanisms frequently get knocked out of whack by travel and long, stressful workdays subject to artificial light.

The focus of the book: our human circadian clock, the neurological mechanism that signals the brain’s pineal gland to produce the hormone melatonin, which helps us sleep. With the wrong lighting pattern, say the authors, the pineal gland turns off or produces melatonin at times of day when we want to be awake and alert, rather than sleepy. Jet lag is the classic example of the circadian clock getting booted sideways. Night shift workers also must struggle with a discombobulated circadian clock. The authors also point out that legions of office workers spend most of the day indoors, where light levels are a fraction of daylight intensity. Then at night, we flood our systems with light from TVs and computer screens.  Even after we turn off the lights, artificial light from outside can pour in and disturb our rhythms.

  The authors also explain how development and age affect circadian rhythms. Puberty causes changes, prompting teens to become sleepy at midnight or 1 a.m., and wakeful at 9 or 10 a.m. Elderly people often become drowsy by 8 p.m., and then find themselves wide awake at 3 a.m. That’s because our circadian clocks weaken as we age, and the pineal gland produces less melatonin.

The authors’ breakthrough message: Once we understand how our circadian rhythm affects our lives, we can control some environmental factors and cure ourselves of insomnia, fatigue and depression. Of course the easiest way to overcome the challenges to our circadian rhythms is to move to a sunny, tropical spot, preferably next to a beach or waterfall. But few of us can afford to do that.

Instead, the authors lay out a therapy regimen. The core of the therapy involves a light box that gives off 10,000 “lux,” the same amount of light you would get if you were walking on the beach 40 minutes after sunrise. The authors recommend that people suffering from sleep problems subject themselves to the light box for a period of time just after they wake. For most people whose circadian rhythms are off, sitting in front of the light box for 30 minutes, ten minutes after waking, will do the trick. For owls, who have trouble getting to sleep until well after midnight, the authors recommend setting an alarm for 7 a.m. and then sitting in front of the light box for a half hour, ten minutes after getting up. Owls should also take care to keep lights low at the end of the day, and to stay away from bright computer screens or television exposure shortly before bed.

The takeaway from this book is that bright light, especially daylight, can be especially energizing. People who are lucky enough to be able to take a 30-minute walk on the beach soon after rising will reap benefits. It’s also a good idea to head out into the sunlight at any time during the day, say the authors.

One other interesting note: The authors say that popular over-the-counter melatonin tablets are no good as sleep aides. The usual drugstore dose of 0.5, 1 or 3 milligrams, puts a much higher level of the hormone into the bloodstream than the body would ever produce, they write. But the authors like melatonin as a tool to set the circadian clock, and they have developed their own low-dose, controlled release tablet that, together with light therapy, works well, they say.

As for jet lag, the authors have a rather complicated prescription, but the core of it, like the prescriptions in the rest of the book, is to subject yourself to bright light for at least a half hour shortly after you wake up. If you can get outside and bask in natural light, then that’s even better.

For more on sleep, The Wall Street Journal ran an excellent piece last weekend by former Forbes writer David K. Randall, now a senior reporter at Reuters, who has written a comprehensive book about the subject, called Dreamland: Adventures in the Strange Science of Sleep. Randall covers the circadian rhythm question and much more.