What Is Delayed Sleep Phase Syndrome?


Written by Afy Okoye

Reviewed by Dr. Michael Breus

Our Editorial Process

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Delayed sleep phase syndrome, frequently called delayed sleep-wake phase disorder, is a sleep disorder that impacts a person’s ability to follow a typical sleep schedule. Adolescents and young adults most commonly experience delayed sleep phase syndrome. 

People with delayed sleep phase syndrome often go to bed two or more hours later than desired and wake up later in the morning. If a person’s wake time is inflexible, these sleep habits can cause problems with work or other commitments. We cover symptoms, causes, risk factors, and treatment options related to delayed sleep phase syndrome.

Symptoms of Delayed Sleep Phase Syndrome

The most common symptom of delayed sleep phase syndrome is the inability to fall asleep and wake up at a desired or socially acceptable time. Going to bed at a later time can lead to a lack of sleep, which can trigger other symptoms: 

  • Difficulty waking up when desired
  • Excessive daytime sleepiness 
  • Fatigue and exhaustion
  • Attention issues and reduced alertness 
  • Pain, including headaches 
  • Impaired judgment
  • Difficulty controlling emotions and mood 

These symptoms can become more severe if a person travels through different time zones, adjusts their work shift, or frequently changes their bedtime for other reasons.

Causes of Delayed Sleep Phase Syndrome

Delayed sleep phase syndrome is primarily caused by a person’s natural sleep-wake schedule mismatching with the schedule of their local environment. 

A person’s sleep-wake schedule is considered a circadian rhythm, which means it’s a daily pattern controlled by their internal clock. This clock uses light and darkness cues to regulate when it’s time to go to bed and when it’s time to wake up. In those with delayed sleep phase syndrome, responses to these cues don’t align with standard bedtimes and wake times.

Since delayed sleep phase syndrome involves a misaligned circadian rhythm, it is considered a circadian rhythm disorder. Experts have outlined several possible factors that may cause the misaligned circadian rhythm associated with delayed sleep phase syndrome: 

  • Irregular work hours
  • A frequently changing sleep schedule
  • Jet lag after traveling across multiple time zones
  • A condition that requires a lot of time in bed 
  • Lack of sunlight for extended periods of time
  • Blindness 
  • Illnesses and injuries that cause brain damage
  • Certain medications 

Research suggests that some rare genetic conditions can cause delayed sleep phase syndrome, specifically those that affect the brain and hormones. For example, Smith-Magenis syndrome impacts the body’s ability to produce melatonin, a sleep-promoting hormone, and can cause disruptions in sleep patterns. 

Experts suggest more research is needed in order to look at the exact cause of delayed sleep phase syndrome. 

Types of Delayed Sleep Phase Syndrome

There are two distinct types of delayed sleep phase syndrome.

  • Aligned: If a person’s internal clock aligns with the natural environmental cues of light and dark, but they still have a later sleep time than desired, it’s considered aligned delayed sleep phase syndrome.
  • Misaligned: When a person’s biological clock runs later than it should given the environment’s light and dark cues, it is called misaligned delayed sleep phase syndrome.

Who Is Most Likely To Be Affected By Delayed Sleep Phase Syndrome?

Delayed sleep phase affects as many as 15% of teens and adults, a much higher rate than advanced sleep phase syndrome, and those with delayed sleep phase are generally younger than those with ASP. It often develops in adolescence and continues into early adulthood, though it may also begin in adulthood. It affects both genders equally. Like ASP, DSP also has a genetic link, and people with a family history of DSP are 3 times more likely to have it as those with no family history of the disorder.

Environmental conditions can lead to the development of Delayed Sleep Phase Syndrome (DSPS) and Delayed Sleep Phase Disorder (DSPD). A lack of morning sunlight exposure, and an overexposure to bright evening sunlight are likely to lead to a shift in the circadian rhythm towards a delayed sleep phase.

Who Is at Risk of Delayed Sleep Phase Syndrome?

There are several risk factors associated with delayed sleep phase syndrome, ranging from lifestyle habits to age. 

  • Age: Research shows that adolescents tend to have later bedtimes than adults, putting them at an increased risk of developing delayed sleep phase syndrome.
  • Work environment: People who work shift work with varying schedules or night shifts, such as flight attendants, pilots, or those who travel frequently for work, are more likely to develop symptoms of delayed sleep phase syndrome. 
  • Lifestyle habits: Lifestyle habits can negatively impact sleep habits. For example, alcohol use before bed, caffeine usage, frequent travel, and exposure to bright lights from TVs and other electronic devices can increase the risk of developing delayed sleep phase syndrome. 
  • Other medical conditions: Certain medical conditions that impact the brain or eyesight can increase a person’s risk for delayed sleep phase syndrome. Mental health issues including depression, bipolar disorder, schizophrenia, and obsessive-compulsive disorder are also associated with delayed sleep phase syndrome. 
  • Sex: People who are assigned female at birth are more likely to develop circadian rhythm sleep disorders during specific transitions in life. These times include throughout pregnancy, after childbirth, and during menopause. 

How Is Delayed Sleep Phase Syndrome Diagnosed?

There are a few assessments doctors use to diagnose delayed sleep phase syndrome, including sleep logs and the morning-eveningness questionnaire. 

Sleep logs are a common recommendation for assessing whether a person is experiencing symptoms of delayed sleep phase syndrome. Over the course of at least seven days, people track when they go to bed and when they wake up. 

If keeping a sleep log is too challenging for a person, an actigraph can be used to track sleep patterns instead. An actigraph is a device worn on the wrist of a sleeper’s non-dominant hand. Most actigraphs track motion, and some models have the ability to track motion and light exposure. 

A self-assessment called the morningness-eveningness questionnaire is another way to look at sleep behavior of people who may have delayed sleep phase syndrome. Results from the assessment can also highlight a person’s chronotype. 

Are You a Wolf Chronotype?

There are four chronotypes, all sitting on different areas of the spectrum from early riser to night owl. People with the wolf chronotype have the most energy when they are able to sleep in. They are more focused in the afternoon hours and also have pockets of energy throughout the evening. 

Research suggests that a person is more likely to have a good night’s sleep if their sleep-wake schedule aligns with their external environment. This ideal sleep rhythm can be challenging to follow for those who are wolf chronotypes and prefer staying up late and sleeping in. 

Delayed sleep wake phase disorder often does not blend well with your social life or work life so I recommend asking your doctor about melatonin as it can help shift the time when you get sleepy to much earlier in the evening.
Dr. Michael Breus

Treatments for Delayed Sleep Phase Syndrome

Treatment for delayed sleep phase syndrome focuses on slowly adjusting a person’s sleep schedule until they follow normal sleep and wake times. 

If people with the disorder are allowed to continue their own sleep routine, they are able to get a similar amount of quality sleep as those who have a normal sleep pattern. Therefore, it might be better for them to continue with their own sleep routine, if their schedules allow it.

When following their own routine isn’t an option due to work or personal obligations, recommended treatment options include lifestyle changes, timed melatonin supplements, and light therapy. The research is promising surrounding the ability to reset sleep patterns to a more normal rhythm using different treatments and therapies.

Lifestyle Changes

In efforts to adjust a sleep-wake cycle, experts may recommend following a routine that includes healthier habits for both daytime and the evening. Exercising earlier in the day, getting exposure to natural sunlight, following a consistent meal schedule, and limiting caffeine and alcohol are habits a person can include in their daytime routine to promote a new schedule. 

In the evening, having a set bedtime, limiting light exposure from electronic devices, and keeping the sleep environment cool and quiet can help foster healthy sleep habits and manage symptoms of delayed sleep phase syndrome. 

Typically, these lifestyle changes are used along with other treatments to help improve the symptoms of delayed sleep phase syndrome. 

Light Therapy

After a person with delayed sleep phase syndrome has made adjustments to their daily routine, a doctor might recommend light therapy. Using a light box in the morning may help a person both fall asleep and wake up earlier. It has also been shown to reduce daytime fatigue. 

Light therapy involves spending time in front of a light box that emits light that’s like sunlight. This light exposure can impact melatonin production, which helps regulate sleep times. 

Before starting light therapy, people should consult with their doctor regarding any potential side effects. 

Timed Melatonin

Although the body naturally produces melatonin, a doctor may recommend melatonin supplements to help people reset their sleep cycle so it matches their environment. Taking melatonin at least an hour and a half before bedtime has been shown to help improve symptoms of delayed sleep phase syndrome by making a person feel tired earlier. 

In those without delayed sleep phase syndrome, the body follows a 24-hour clock. Melatonin levels decrease throughout the early morning to create a sense of being alert and slowly increase in the evening, prompting sleepiness. Some people with delayed sleep phase syndrome experience a delay in this same evening increase in melatonin.

Melatonin supplements are not regulated by the Food and Drug Administration (FDA). Before taking a melatonin supplement, it’s important to talk to your doctor about appropriate dosage and possible side effects.

Frequently Asked Questions About Delayed Sleep Phase Syndrome

Is delayed sleep phase syndrome related to ADHD?

Delayed sleep phase syndrome is common in people with attention deficit hyperactivity disorder (ADHD). Approximately three out of four adults with ADHD also experience symptoms of delayed sleep phase syndrome. Daytime sleepiness has also been reported in those with ADHD.

However, more research needs to be conducted to fully understand the connection between ADHD and delayed sleep phase syndrome.

Can you cure delayed sleep phase syndrome?

While there are several treatment options that show promising results in resetting a person’s sleep schedule, there isn’t a cure for delayed sleep phase syndrome.

Studies suggest that causes of delayed sleep phase syndrome are a result of a combination of different factors, including genetics, that alter a person’s internal clock, causing disruptions in normal sleep patterns.

Treatment options for delayed sleep phase syndrome serve as an effort to reset that internal clock and reduce symptoms in order to promote healthy sleep habits.

Is it common to develop delayed sleep phase syndrome as an adult?

Delayed sleep phase syndrome usually develops during adolescence and young adulthood rather than later in adulthood. Research shows that less than 2% of cases of delayed sleep phase syndrome occur in adults. However, if a person develops delayed sleep phase syndrome early in life, they may also carry it into adulthood.

About The Author

Afy Okoye

Staff Writer, Sleep Health

Afy is a writer and creative strategist in San Francisco with a master’s degree in international health policy from the London School of Economics. She has written for VeryWell Health, BlackDoctor.org, and Paste magazine and edited peer-reviewed journal manuscripts for Elsevier. Afy says her work with The Sleep Doctor is anything but “sleepy.” She enjoys the opportunity to learn new information and share knowledge that gives people the power to make better choices. Afy also likes to read non-fiction, do creative writing, and travel solo.

  • POSITION: Side Sleeper
  • TEMPERATURE: Hot Sleeper

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