7 Sleep Disorders: Causes, Symptoms + Definitions

Written by
Purple Staff
, Illustrations by
Purple Staff
Last Updated
December 7, 2022
min read

Practicing good sleep hygiene, following a consistent routine, and avoiding artificial light exposure near bedtime are some simple and practical ways you can treat sleep disorders. However, it isn’t always quite as simple.

Chronic fatigue, aches, pains, constant stress, and a restless mind – are only a few of the many symptoms of sleep disorders. These conditions can wreak havoc on your quality of life, causing stress at night and poor physical and mental aptitude during the day.

Here, we break down some of the most common sleep disorders and how you can treat them. 

What Are Sleep Disorders?

Sleep disorders are conditions that affect the way you sleep. Oftentimes, a sleep disorder will keep you from getting enough restorative sleep to feel alert and fully functional the next day. 

If you are experiencing chronic poor sleep, you’re not alone. Approximately 50-70 million Americans suffer from sleep disorders. Thankfully, there are natural and medical treatments that people can undergo to get the rest they need. 

What Happens When A Person Doesn’t Get Enough Sleep?

When a person doesn't get enough sleep, they experience mental impairment, become more prone to accidents, and are more prone to certain risk factors for chronic diseases.

Chronic sleep deprivation can result in short-term problems such as:

  • Lack of focus
  • Irritability
  • Poor decision-making
  • Slower reaction time
  • Impaired memory
  • Depression and anxiety

Studies have shown that sleep deficiency also puts you at a greater risk of being involved in motor vehicle crashes and accidents involving heavy machinery. 

Chronic sleep deprivation is also associated with serious long-term health issues such as hypertension, cardiovascular disease, stroke, diabetes, and obesity. 

How Common Are Sleep Disorders?

Sleep disorders are fairly common and occur in 50 to 70 million people in the US alone. 

It should be noted that, while most people should get about 7 to 9 hours of sleep every night, falling outside of "normal" sleep patterns once in a while doesn't mean that you have a sleep disorder. 

However, if you find that your sleep issues are doing any of the following, it's best to consult with a doctor to get assessed for a sleep disorder:

  • Causing you distress
  • Getting in the way of work/school/relationships
  • Bringing about significant changes in your mood or mental health
  • Making you more prone to accidents
  • Generally affecting the quality of your life

How Many Types Of Sleep Disorders Are There?

There are around 90 different types of sleep disorders. They are often categorized as:

Circadian Rhythm Sleep Disorders

Circadian rhythm disorders involve problems with a person's internal clock. Everyone has a master clock in the brain called a suprachiasmatic nucleus (SCN), which regulates a range of biological functions and controls our sleep-wake cycle. This clock is sensitive to things like light, dark, and temperature. 

Melatonin suppression brought on by overexposure to artificial light has been linked with circadian rhythm disorders.

Here are a few examples of circadian rhythm disorders:

  • Delayed sleep-wake phase disorder: Also called delayed sleep phase syndrome, this disorder causes sufferers to sleep and wake at least two hours later than what is considered normal. People with DSPD are often characterized as "night owls" and will stay awake past midnight and wake in the late morning to early afternoon.
  • Advanced sleep phase disorder: The opposite of DSPD, advanced sleep phase disorder causes people to sleep and wake several hours earlier than most. This is common among the elderly and those with Alzheimer's disease.
  • Non-24-hour sleep-wake rhythm disorder: This is characterized by a sleeping pattern that continually shifts later and later each day. People with N24SWD do not have a fixed bedtime and waking time and often feel "out of sync" with the rest of the world.
  • Irregular sleep-wake rhythm disorder: People with this disorder have no discernible pattern in their sleep and wake times. They tend to take several naps throughout a 24-hour period.


Insomnia is often described as an inability to fall and/or stay asleep. Mild insomnia symptoms might include waking up throughout the night or struggling to fall asleep for an hour or more after getting into bed. Severe, chronic insomnia may result in the complete inability to sleep at night and extreme fatigue, or hypersomnia, during the day.


Also known as hypersomnolence, this is a group of sleeping disorders characterized by excessive sleepiness. The disorders that fall under hypersomnia include:

  • Narcolepsy: This is a neurological disorder that causes people to suddenly fall asleep at any given time.
  • Idiopathic hypersomnia: This is characterized by an “insatiable need to sleep that is not eased by a full night’s slumber”.
  • Klein-Levin syndrome: Also known as "Sleeping Beauty Syndrome", this disorder causes bouts of severe sleepiness alternating with periods of normal sleep and wakefulness. People with KLS sometimes need 16 to 18 hours of sleep a day for several days or even weeks.


This includes sleep disorders that cause sufferers to experience unwanted events or experiences during or as they drift off to sleep. Disorders that fit under this category include:

  • Night terrors
  • Sleep paralysis
  • Sleepwalking 
  • Sleep eating
  • REM sleep behavior disorder
  • Exploding head syndrome
  • Bedwetting

Sleep-Related Breathing Disorders

These are disorders that cause breathing difficulties during sleep. This includes:

  • Child sleep apnea
  • Central sleep apnea
  • Obstructive sleep apnea
  • Snoring

Sleep-Related Movement Disorders

These disorders cause sufferers to make sudden movements during or moments before sleep. Examples of sleep-related movement disorders include:

  • Restless leg syndrome
  • Bruxism or teeth grinding
  • Hypnagogic jerks or sleep starts

Who Is More Likely To Have A Sleep Disorder?

According to the American Academy of Sleep Medicine, women are more likely to suffer from sleep disorders than men. Women are also more "affected by the burden of their symptoms".

What Are The Symptoms Of Sleep Disorders?

The most common symptoms of sleep disorders are insufficient sleep, excessive sleepiness, fatigue, irritability, and cognitive impairment. However, given that there are about 90 different kinds of sleep disorders, it should be noted that different sleep disorders will naturally present differently. 

How Are Sleep Disorders Diagnosed?

Sleep disorders are often diagnosed by physicians using polysomnography or a sleep study. Usually, patients will be asked to stay at a sleep center where they can be observed overnight. The process involves recording brain waves and reading things like blood oxygen levels, heart rate, breathing, and eye movements. 

Some doctors also ask patients to keep a sleep diary. Having personal documentation of sleep patterns can help doctors recognize the factors that cause sleep problems. 

What Are The Treatments For Sleep Disorders?

Sleep disorders can be treated with medication, therapy, and/or lifestyle changes, routines, and home remedies. For practical treatments for common sleep disorders, check out the following section.

7 Common Sleep Disorders And How To Treat Them

No matter which treatment option you prefer, the first step to addressing a sleep disorder is to diagnose your problem. Here are some of the most common sleep disorders and effective treatments you can do to address them:


Insomnia is the most common sleep disorder in the world and is characterized by an inability to fall asleep or stay asleep through the night. Insomnia in children can also present as behavioral problems, poor impulse control, and difficulty regulating emotions.

The most common causes of insomnia are stress, anxiety, drug and alcohol use, diabetes, and some medications.

You are also more likely to suffer from insomnia as you get older. This is brought on by changes in activity levels, chronic pain, certain medications, and the natural advancement of one's internal clock as one ages.


Somnolence is the scientific term for excessive sleepiness or drowsiness. Also known as hypersomnia, hypersomnolence is characterized by:

  • Moderate to severe daytime sleepiness
  • Sleeping longer than average each night
  • Feeling fatigued and having difficulty waking up despite getting enough or excess amounts of sleep
  • Anxiety and irritability
  • Low energy
  • Headaches
  • An inability to focus

Causes for this condition are wide-ranging and include stress, jet lag, work-related sleep problems, insomnia, and anxiety. It can also be caused by some medical conditions like sleep apnea) and medications.

Restless Leg Syndrome

Restless leg syndrome (RLS) causes an uncontrollable urge to move your legs. This movement disorder occurs while you’re awake, making it very difficult for the sufferer and their partner to relax and fall asleep.

Restless leg syndrome is more common in women, especially pregnant women. This movement behavior disorder is usually caused by a lack of mobility or sitting still for periods of the day. Those who suffer from RLS may notice their symptoms worsening after having to sit through a long movie, flight, or lecture that day.

Sleep Apnea

Sleep apnea is a condition caused by the partial or complete closing of the throat during sleep. There are multiple types of this condition, including central sleep apnea (CSA) and obstructive sleep apnea (OSA). This disorder is associated with loud, habitual snoring or wheezing during sleep, gasping for air during sleeping, and waking up with a dry mouth.

Aside from this, sleep apnea can also be very straining on relationships. Those with sleep apnea can suffer from insomnia and somnolence as well, as they are often unable to stay asleep or move through each sleep phase to complete a sleep cycle.

While daytime sleepiness is a common issue for adult sufferers. However, sleep apnea in children is more likely to result in behavioral problems. Childhood obstructive sleep apnea syndrome can cause inattentiveness, hyperactivity, and irritability. This leads children with sleep apnea to perform more poorly in school compared to their peers. Adolescent sleep apnea may present similarly.

Sleep apnea is caused by several factors, including having a narrow airway, being overweight, and having a family history of OSA. Sleeping flat on your back can exacerbate symptoms of sleep apnea, so doctors recommend sufferers elevate their heads and neck or sleep on their sides to improve their sleep. 


Also called somnambulism, sleepwalking is a condition commonly caused by stress, a change in your sleep schedule, illness, or sleep deprivation.

Unfortunately, there aren’t many things that you can do to avoid sleepwalking besides decreasing stress and trying to get plenty of fulfilling sleep. As a lack of sleep often correlates to increased stress, these go hand in hand.

Sleep Eating

Sleep-related eating disorder (SRED) is a condition similar to sleepwalking and may affect sleepwalkers. Those affected eat and even prepare meals while asleep. This disorder is not well understood, but it is believed to be caused by stress, anxiety, eating disorders, or withdrawal from alcohol or nicotine. 

It is more common in adults, and those with other sleep disorders like sleepwalking or restless leg syndrome are more likely to experience SRED. It is also commonly associated with confusional arousals, a type of sleep disorder that leads to feelings of confusion and strange behaviors just as the person wakes up. 

Night Terrors

Also called sleep terror disorder, “night terrors” is a condition that causes a sleeper to show signs of extreme fear and distress while sleeping. Unlike nightmares, which can cause nighttime awakenings, night terrors do not often lead to sleep disturbance. People with night terrors may shout, sit up, kick, flail, or stare blankly out of fear, but often do not remember all or most of their terrors the next day.

Doctors don’t yet understand night terrors very well, but luckily, they are believed to be harmless. These sleep problems can be caused by an excessive lack of sleep, stress, illness, or changes in your sleep schedule or environment. They also seem hereditary and may be triggered by RLS, sleep apnea, and alcohol use.

Night terrors are more common sleep disorders in children than adults, so medication is rarely recommended. 

Sleep Disorders FAQs

What are the most common sleep disorders?

The most common sleep disorders are insomnia, hypersomnia, sleep apnea, restless leg syndrome, sleepwalking, sleep eating, and night terrors.

What are the most common causes of sleep problems?

The most common causes of sleep problems are stress, poor sleep habits, and overexposure to artificial light.

What sleep disorders qualify for disability?

In the US, some of the sleep disorders that qualify for disability are insomnia and sleep apnea