Sleep challenges affect more than 70% of individuals with Prader-Willi syndrome (PWS). Excessive daytime sleepiness, disrupted nighttime sleep, altered REM patterns, and sleep-disordered breathing all contribute to a complex sleep profile that affects daily life. Sleep in PWS is not simply about feeling tired. For all individuals, neurotypical or otherwise, sleep impacts:
- Emotions
- Cognition
- Behavior
- Performance
- Family Dynamics
- Health
Emerging research suggests that sleep directly influences behavior, emotional regulation, and mental health — making it a critical area for clinical attention and research.
Why are Sleep Challenges so Common in PWS?
Sleep difficulties in PWS are biologically driven and often persist even when nighttime sleep appears adequate.
High Rates of Sleep Disorders
Sleep-disordered breathing is extremely common in PWS. A meta-analysis by Sedky et al., 2014 (Sleep Medicine Reviews) found a very high prevalence of obstructive sleep apnea (OSA) in individuals with PWS, with rates approaching 80% in children.
In addition, narcolepsy-like features and excessive daytime sleepiness are reported in up to 35% of individuals with PWS (Maas et al., Sleep, 2009). These symptoms are linked to abnormalities in REM sleep regulation and central hypersomnia.
Circadian Rhythm Differences
Beyond OSA and narcolepsy-like symptoms, research suggests that circadian rhythm regulation — the body’s internal 24-hour clock — is disrupted in PWS at a cellular level.
A study by Victor and colleagues found that neurons derived from individuals with PWS show significantly altered circadian period lengths compared with neurotypical controls.
These findings are important because the circadian clock influences sleep timing, hormone release, alertness, and metabolism. An altered circadian period could contribute to daytime sleepiness and difficulty maintaining consolidated wakefulness, even when total sleep time at night seems sufficient.
Neurotransmitters and the Orexin System
Sleep and wakefulness are regulated by a delicate balance of neurotransmitters in the hypothalamus, a part of the brain known to be negatively impacted by PWS.
One of the most important wake-promoting systems involves orexin (hypocretin). A landmark study by Tauber et al. (2004, Journal of Clinical Endocrinology & Metabolism) found reduced hypocretin levels in some individuals with PWS and excessive daytime sleepiness, supporting the idea that central wake-promoting pathways may be altered in PWS.
Research Shows Sleep and Mental Health Are Connected
Conditions such as anxiety, depression, and ADHD may be linked to insufficient signaling from wake-promoting neurotransmitters in the brain.
This connection is supported by broader sleep research showing that disrupted sleep and circadian misalignment increase risk for mood disorders, attention difficulties, and behavioral dysregulation in both pediatric and adult populations (Goldstein & Walker, 2014, Nature Reviews Neuroscience).
Within the PWS community specifically, a 2022 analysis of nearly 900 individuals enrolled in the Global PWS Registry found that those with excessive daytime sleepiness had a significantly higher frequency of anxiety, depression, and psychosis compared to those without excessive sleepiness.
These findings demonstrate a meaningful correlation between sleep disturbances and increased behavioral challenges and mental health concerns.
In other words, sleep disruption is not isolated. It may contribute to irritability, anxiety, mood instability, impulsivity, and difficulties with attention and emotional regulation — all areas already vulnerable in PWS. On top of that, parents of those with PWS report that their own sleep often is disrupted when caring for their child with PWS (Kayadjanian et al 2018), and this may lead to more overall stress for the family.
Is Your Loved One With PWS Sleepy?
Sleepiness in PWS is not always obvious. It can also present in subtle — and sometimes surprising — ways. In the absence of obvious sleepiness, you may observe:
- Falling asleep at unusual times and in unusual places
- Trouble focusing
- Slower processing speeds
- Increased irritability
- Emotional outbursts
- Rigidity
- Anxiety
- Overactivity, including increased movement
Excessive sleepiness can be evaluated and measured through formal sleep testing, including:
- Polysomnography (overnight sleep study) to assess breathing, oxygen levels, and sleep architecture
- Multiple Sleep Latency Testing (MSLT) to objectively measure daytime sleepiness and screen for narcolepsy
- Clinical sleep questionnaires and behavioral assessments
Current Treatment Approaches
FDA-approved treatments for sleepiness are limited.
Modafinil (brand name Provigil) is an FDA-approved, wake-promoting medication commonly used to treat narcolepsy and other causes of excessive sleepiness, such as sleep apnea or shift-work disorder.
Modafinil is sometimes prescribed off-label to help manage excessive daytime sleepiness in individuals with PWS. In an open-label study of modafinil, all 9 participants with PWS reported improvements in daytime sleep. Because it is not FDA-approved for this indication, however, some families may face access challenges.
The TEMPO Study: A Phase 3 Clinical Trial of Pitolisant for Daytime Sleepiness
TEMPO is a Phase 3 clinical trial evaluating pitolisant for excessive daytime sleepiness in individuals with PWS.
Pitolisant works differently from traditional stimulants. It acts on the brain's histamine system, which helps regulate wakefulness. By enhancing histamine signaling, pitolisant may help improve alertness without the same mechanism as stimulant medications.
The TEMPO trial is open and enrolling participants with PWS ages 6 years and older who have excessive daytime sleepiness. A 100% virtual participation option is available! After the 12-week double-blind study is complete, all participants have the option of enrolling in an open-label extension study where everyone receives Pitolisant.
Learn more about the TEMPO trial at www.tempopwsstudy.com
From Understanding to Action: Advancing Sleep Research in PWS
Sleep intersects with behavior, emotional regulation, mental health, and more. Research is helping us better understand the impact, and clinical trials, like TEMPO, are helping us evaluate potential solutions. Together, these represent progress — moving from observation to evidence, and from evidence to action.
Interested in learning more about sleep issues in PWS? Here are three resources you may find useful:
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Video: 2023 recorded presentation with Dr. Jessica Duis, shares the presentation and management of sleep disorders in PWS.
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Video: 2021 recorded presentation with Dr. Aaron Chidekel, Chief of Pulmonology, Nemours Children’s Health, explores the biological drivers of sleep disruption in PWS and practical approaches for evaluation and treatment.
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Blog: Insights into the Sleep, Seizure, and Psychiatric Behaviors in PWS
References
- Sedky K, Bennett DS, Pumariega A. Prader-Willi syndrome and obstructive sleep apnea: a meta-analysis. Sleep Med Rev. 2014.
- Maas APHM et al. Sleep abnormalities in Prader-Willi syndrome. Sleep. 2009.
- Victor AK et al. Circadian Rhythm Defects in Prader-Willi Syndrome Neurons (preprint, 2025)
- Tauber M et al. Low cerebrospinal fluid hypocretin levels in Prader-Willi syndrome. J Clin Endocrinol Metab. 2004.
- Goldstein AN, Walker MP. The role of sleep in emotional brain function. Nat Rev Neurosci. 2014.
