Note that Circadian Sleep Disorders Network is not affiliated with any pharmaceutical, medical device, or other company.
Circadian Rhythm Sleep Disorders (CRSDs or CRDs) are neurological disorders in which the sleep-wake cycle is out of sync with the day-night cycle. These include in particular Delayed Sleep Phase Disorder and Non-24-Hour Sleep-Wake Disorder. Also included are Advanced Sleep Phase Disorder, Irregular Sleep Wake Disorder, and Shift Work Disorder, which are defined here.
Delayed Sleep Phase Disorder (DSPD), also called Delayed Sleep Phase Syndrome (DSPS), is characterized by an inability to fall asleep until very late at night, with the resulting need to sleep late in the morning or into the afternoon. Questions? See our DSPS Q&A.
Advanced Sleep Phase Disorder (ASPD), also called Advanced Sleep Phase Syndrome (ASPS), is the opposite. It is characterized by falling asleep very early in the evening, and waking up in the wee hours of early morning, unable to sleep further.
Non-24-Hour Sleep-Wake Disorder (Non-24), also called Free-Running Disorder (FRD), is a condition in which a person's day length is significantly longer than 24 hours, so that sleep times get later each day, cycling around the clock in a matter of days or weeks. Questions? See our Non-24 Q&A.
Some people use the term reverse sleep, referring to the fact that sometimes people with DSPD and Non-24 end up sleeping during daylight and being awake at night.
We are asking our members and followers to give our brochure, and/or our Q&A booklets, to their sleep doctors and their general doctors on their next visits. It is vital to all of us suffering from circadian disorders that more doctors and their support staff understand these disorders and how disruptive they can be. The more doctors who know about us, the more patients we can reach, inform, and support. And the larger our membership, the more credible our voice on behalf of all people with circadian sleep disorders.
You can print out the brochure on U.S. letter paper (8½x11) or on A4 paper (non--U.S.). Booklets can be printed for DSPS or for Non-24 (the same file can be printed on either U.S. or A4 paper). Alternatively you can email us at to request a printed copy of any or all these documents (please specify which, and how many you really need). Be sure to include your name and full postal address. We will send these at no charge to you.
The Night Girl Finds a Day Boy - a true story about a DSPD person and a normal-time sleeper falling in love and making it work - is coming to Amazon video.
Circadian Sleep Disorders Network is a signatory on the just released AASM position paper "Sleep is essential to health: An American Academy of Sleep Medicine position statement." Lots of good proposals and conclusions, including "Healthy sleep requires adequate sleep duration, appropriate timing, regularity, the absence of sleep disorders, and good quality..." [emphasis added].
CSD-N President Peter Mansbach "attended" (virtually) the SLEEP2021 conference presented by AASM and SRS from June 10 - 13 . Here are some takeaways:
1. It's not the light from the screens, it's the engagement. According to Dr David A. Reichenberger, screen use in adolescents suppresses melatonin, delays sleep and shortens time asleep. But he compared one group who texted and played games with another group that watched videos that were not very exciting. Only the first group suffered delays in their sleep time. (Note: these were presumably normal sleepers; some of us with circadian disorders may be more sensitive to light.)
2. Dr Emmanuel Mignot, expert narcolepsy researcher, again said that abnormal circadian phase is a big problem in testing for narcolepsy type 2 (without cataplexy).and gives rise to a lot of false positives.
He also said type 2 narcolepsy may be a disease invented by a test: the MSLT (Multiple Sleep Latency Test) has a 4% false positive rate (this is in all people, not specifically circadian-disordered patients), so if you test everybody, 4% are positive, but based on symptoms only 0.05% actually have narcolepsy. The false positives would far exceed the number of people truly having narcolepsy.
3. Dr Bert Staels arranged for some cardiac surgeries to be performed in the afternoon. Bad outcomes were more frequent in morning cardiac surgeries than in afternoon ones. Nevertheless, hospitals will continue to schedule nearly all surgeries in the morning. Another observation: shift workers also had worse outcomes after cardiac surgery.
4. Dr Colleen McClung studied connections between circadian rhythm and mood disorders. She observed that lower amplitude circadian rhythm was associated with mood disorders and anxiety. Also that lithium improved circadian rhythm amplitude. (She inferred amplitude from core body temperature variation and other parameters such as gene expression, and SCN activity in animal models.)
Late chronotypes are associated with psychiatric disorders. (I would add: late chronotypes' schedules don't fit well with society's expectations, leading to more stress, leading to psychiatric disorders.)
5. Dr Allison Harvey spoke about the connection between mental illness and sleep and circadian rhythms. Over half of all mentally ill people have not just one, but more than one diagnosable sleep disorder. Mental illness is associated not only with circadian rhythm mismatch to the light-dark cycle, but also with internal desynchrony (different organ systems being on different clocks). Sleep and circadian intervention often improves the comorbid mental disorder too. Her focus was on finding sleep and circadian interventions that work across many different sleep and circadian disorders, otherwise diagnosis and treatment is too complicated for wide implementation in typical mental treatment settings.
6. Marta Garaulet spoke about meal timing in obesity and weight loss. Late eaters lost less weight when dieting, were more obese, and had higher metabolic risk. "Late" was defined as the midpoint between start of breakfast and end of dinner being after 3 pm. (I don't think there was any effort to account for subjects' internal clock.) Also, longer nighttime fasting (from dinner to breakfast) led to more weight loss when dieting.
7. Daylight saving time was the subject of panel discussion. Everyone agrees that the changeover from standard time to daylight saving time causes health problems including a higher incidence of heart attacks and traffic accidents. Interestingly, the western side of any time zone - already getting up earlier relative to the sun - has worse outcomes than the eastern side. It was noted that blind non-24 patients did not shift just because the clocks shifted - they continued on their internal rhythm.
So everyone agreed that we should not switch from standard to daylight saving time and back. But should we have year-round standard time or year-round daylight saving time? Many in the sleep research community believe that permanent standard time is healthier. Since people have to get up at the same clock time for work or school, there is less morning sunlight. It is also dark later in winter, leading to more traffic accidents, school children walking to school in the dark, and more depression. Late chronotypes (DSPD people being the extreme) are even more at risk, since they now have to get up an hour earlier relative to their internal clock.
One panelist felt that the evidence was not sufficiently conclusive to warrant a nationwide change of this magnitude. Another panelist was a politician in the Utah legislature as well as a medical doctor, and pointed out that politically, year-round standard time was a non-starter. It was going to be year-round daylight saving, or keep the present system. It was pointed out by someone else that we and other countries have tried permanent daylight time before, and once the dark winter mornings rolled around, the public demanded a return to standard time.
8. There were a series of short talks on Moving Beyond Circadian Phase, talking about circadian amplitude, with Dr Ron Anafi and others. They differentiated between "strength" (amplitude) and "stiffness" (resistance to change in timing and also day-to-day variability). Overall, amplitude could be described by melatonin level, activity level, core body temperature variation, or brain activity. The focus of these talks, however, was on transcriptional gene expression and its variation over 24 hours. They've looked at thousands of genes, and methods are being developed to characterize the circadian cycle and its amplitude. In general, amplitude decreases with age, insufficient sleep, unnatural light exporsue, and metabolic challenges like eating at the wrong time.
9. Dr Garrett Hisler spoke about his research on risky behaviors: delayed circadian misalignment is associated with taking greater risks of loss, but less risk for potential gain. Advanced misalignment did not show this effect.
10. Finja Marten presented a talk on sleep and ADHD in adolescents and young adults. In her study, 70% of those with ADHD had sleep problems, compared with 6% of those without ADHD. (My question: which causes which?)
CSD-N board member Samuel Bearg was recently interviewed on Handi-Link about his CRD and CRDs in general. Check it out here. (Listen to the "modified" version, which corrected an error in our name.)
One of the earliest members of CSD-N is working on his PhD and seeks people willing to be interviewed. He writes:
I am a PhD student at the University of Leeds seeking to recruit people with diverse sleeping times or diagnoses of a circadian rhythm sleep disorder to interview about the social and historical development of our knowledge about circadian rhythms and their disorders....
The interviews will take up to one hour and be conducted online or by telephone at flexible times to suit participants. The interviews will broadly cover your experiences and understandings of sleep timing, the various ways in which sleep timing may be controlled and the role of sleep timing in society.
This study has been reviewed and received a positive opinion from the Faculties of Business, Environment and Social Sciences Research Ethics Committee, 22nd March 2021, reference: AREA 20-075.
Thank you for your time,
Centre for Disability Studies
University of Leeds
We urge you to contact him to be interviewed.
CSD-N Board member Rachel Amon hosted @WeAreDisabled on May 3 on Twitter. She explained DSPD and referred people to our website for more information. View the Twitter session here.
CSD-N board member Andrew Cowen gave a talk at the Orphan Drug Conference on April 28. He explained Non-24, and talked about the difficulty of obtaining Hetlioz and insurance coverage for it. You can view a recording here.
CSD-N board member Alexandra Wharton was interviewed on Vice News on March 15. She talked about her experience with DSPD, and the particular difficulty of shifting the clocks an hour ahead when we switched to daylight saving time the day before. Watch this segment on Youtube.
The Circadian Sleep Disorders Network (CSD-N) contributed to a white paper that was recently published in the prestigious journal SLEEP. Authored by leaders in the field of circadian medicine, this paper has the potential to influence the direction of research on circadian rhythm sleep-wake disorders (CRSWDs).
Workshop report. Circadian rhythm sleep-wake disorders: gaps and opportunities identifies gaps in the diagnosis and treatment of CRSWDs and defines areas of urgently needed research.
The paper presents the results from a workshop cosponsored by the Sleep Research Society (SRS) and the Society for Research on Biological Rhythms (SRBR). CSD-N contributed through our detailed Needed Research document, which is listed as Reference 16 in the white paper.
This review of the many gaps in our knowledge of CRSWDs is timely in light of the increased attention to circadian rhythms in many areas of medicine, and is so welcome to the many patients with these disorders for whom the current treatments fail.
We are generally pleased that many of the points we made in our Needed Research document were, in fact, included in this report. It clearly underscores the poor understanding of causes of these disorders, the absence of good diagnostic biomarkers, and the lack of effective treatment. It acknowledges inconsistent definitions of the disorders, and lack of good data on prevalence. Numerous other issues of concern to us have also been included.
Three points, however, we wish had been made more clearly: First, the need for patients' subjective improvement - not just laboratory measurements - in evaluating treatment success is mentioned, but only once. Second, while the white paper acknowledges the likelihood of different subtypes of CRSWDs with different underlying causes, and also acknowledges that efficacy of existing treatments is not well understood, it doesn't seem to clearly make the connection that the different subtypes likely require different treatments — and therefore any one treatment would exhibit low success rate when applied to the entire patient population. Finally, it doesn't seem to acknowledge that so many DSPWD patients are still tired, even while sleeping according to their body's internal clock.
CSD-N wishes to thank its patient community for their comments on social media, which informed our Needed Research document and from there the white paper. Thanks also to the workshop participants for including our viewpoint, and Dr Elizabeth B Klerman who contacted us and was our liaison to the workshop. Dr Klerman is also a member of the CSD-N medical advisory board.Archived News 2020
This is a free mailing list support group for people with DSPS and Non-24 to share their experiences. It's a good place for people just discovering these disorders to hear how others deal with them, as well as for long-time participants to get support and to provide support to others. There are often discussions of evolving treatment, useful to all. For further information, and to sign up, go to www.circadiandisorders.org/list.
Note that membership in Circadian Sleep Disorders Network and membership on this email list are completely separate.
Circadian Sleep Disorders Network is affiliated with this email list, and our volunteers assist the list administrator with some chores. CSD-N was formed by participants on this list, and many of our members post regularly. But we have no control over what appears or who can join, and list membership is completely separate from membership in CSD-N.
Once you've signed up for the list, you post by sending an email to Everyone on the mailing list receives that post as an email, and you receive everyone else's posts as emails. If you don't like to get separate emails, you can opt to receive in digest form, typically one email a day containing all the day's posts. You make that selection after signing up by logging in (using the password you created when signing up for the email list) at www.circadiandisorders.org/list.
There are some rules:
The rules that the list software enforces are
An additional rule is PLEASE do not just reply to a message with a subject line containing "Niteowl Digest, Vol xxx, Issue xxx". That is obviously not informative and if you aren't careful you may include the whole list of messages in the Digest, making your message too large for the list.
Digest or not, it is a good idea to trim whatever you are replying to leaving just enough for people to know what you are replying to.
Once you've signed up for the list, you can also browse previous posts in the archive at
There is also a mirror of the archive on Yahoo at https://groups.yahoo.com/neo/groups/nite-owl/info. This is useful when the primary archives are not working, as sometimes happens. Login to your Yahoo account, or create one (free) - link is at the top right on that page. Then you have to join the Yahoo copy of the list - this is separate from signing up for the list itself - there is a button on the Yahoo page to do this.
To unsubscribe from the Niteowl email list go to
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If you do not know your list password, send email to
with PASSWORD in the subject line. This email must come from the same email address that you subscribed from (which is the one your incoming Niteowl list emails go to). Your password will be sent to you at that address.
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Our brochure is geared to the general public, to introduce DSPD (DSPS) and Non-24 to people experiencing symptoms of these disorders, and to their families.
Please distribute it to anyone who may be interested.
Print on lightly colored paper for some color, if you like. We used ivory.
|Brochure - web display||
Print on US letter size paper, PDF
Print on A4 size paper, PDF
The web display version shows the brochure panels in easy-to-read order. The print versions are meant to be printed out on both sides of a sheet of paper, then folded in thirds, creating a brochure. (In the print version, the panels will appear out of order on-screen.)
We have posted documents describing DSPD (DSPS) and Non-24, in an easy to read Question-and-Answer format. These are designed to give to family members, friends, employers, and school personnel, to help them understand these disorders. Feel free to print and distribute these. There are two different (but similar) versions, one for DSPD and the other for Non-24:
|DSPD Q&A - web||printer||booklet*|
|Non-24 Q&A - web||printer||booklet*|
The web formats display nicely in your browser.
The printer versions are formatted by your browser for printing a multi-page document.
The booklet forms are pre-formatted PDF files that you can print on two sides of a single sheet of paper, which then folds in half into a booklet.
* When printing the booklet, be sure to flip on the short edge (select this option if you have a double-sided printer).
|Spanish:||DSPS Preguntas y Respuestas - web||printer|
|No-24 Preguntas y Respuestas - web||printer|
|German:||DSPS F&A - web||printer|
|Non-24 F&A - web||printer|
We also have a one page Basic Fact Sheet that introduces DSPD and Non-24 to people who don't know about them. It's a quick and easy read, just the basics.
Former board member and artist Lily Style has created an infographic describing Circadian Rhythm Sleep Disorders. View it in your browser at www.circadiansleepdisorders.org/docs/CRSDGraphic.php. Feel free to repost the graphic to help raise awareness.
You can print it directly from your browser (we suggest making the browser window full screen - the image will resize). We are also posting JPG images in various proportions for printing directly on different sizes of paper:
We are offering merchandise (mugs, T-shirts, tote bags, bumper stickers, and a messenger bag) with our name and logo through CafePress,
www.cafepress.com/circadiansleepdisordersnetwork. (Note: if you just search CafePress you will find this merchandise, but at a higher price!)
Circadian Sleep Disorders Network is a Coalition Partner of Start School Later. We understand only too well the difficulties many teens have with early school start time, and we support the move to start school later.
The first time you go to smile.amazon.com you will be asked to confirm Circadian Sleep Disorders Network as your charity. Amazon will remember your selection. But you do have to go to smile.amazon.com instead of simply amazon.com, for each purchase, if you want 0.5% of that purchase to go to CSD-N. Note that you pay the same amount either way - through Smile the 0.5% goes to us, otherwise it goes to Amazon.
We have already received several contribution checks from Amazon! Please select Circadian Sleep Disorders Network as your charity. smile.amazon.com
Also available on the the Amazon Shopping app on your phone. How it works there:
Amazon and the Amazon logo and AmazonSmile and the AmazonSmile logo are trademarks of Amazon.com, Inc. or its affiliates.
This is a list of refences added to our Info page since the last newsletter. The newsletter lists references added since the previous newsletter. These are generally available to members only.
This web site is intended to provide generic information about Circadian Rhythm Sleep Disorders, and
is not intended to replace discussions with a healthcare provider.
You should not use the information on this website for diagnosing or treating a medical or health condition.
All decisions regarding patient care should be made with your healthcare provider.
Office: 4619 Woodfield Rd, Bethesda, MD 20814
Phone: By appointment only, please.
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