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What are Sleep Disorders?

Sleep disorders (or sleep-wake disorders) involve problems with the quality, timing, and amount of sleep, which result in daytime distress and impairment in functioning. Sleep-wake disorders often occur along with medical conditions or other mental health conditions, such as depression, anxiety, or cognitive disorders. There are several different types of sleep-wake disorders, of which insomnia is the most common. Other sleep-wake disorders include obstructive sleep apnea, parasomnias, narcolepsy, and restless leg syndrome.

Sleep difficulties are linked to both physical and emotional problems. Sleep problems can both contribute to or exacerbate mental health conditions and can be a symptom of other mental health conditions.

About one-third of adults report insomnia symptoms and 4-22% meet the criteria for insomnia disorder.1

Importance of Sleep

Sleep is a basic human need and is critical to both physical and mental health. There are two types of sleep that generally occur in a pattern of three-to-five cycles per night:

  • Rapid eye movement (REM) – when most dreaming occurs
  • Non-REM – has three phases, including the deepest sleep

When you sleep is also important. Your body typically works on a 24-hour cycle (circadian rhythm) that helps you know when to sleep.

How much sleep we need varies depending on age and varies from person to person. According to the National Sleep Foundation most adults need about seven to nine hours of restful sleep each night, preferably with consistent sleep and wake times. 

Many of us do not get enough sleep. A third of adults report that they usually get less than the recommended amout of sleep and only about 30% of high school students get at least eight hours of sleep on an average school night.2 An estimated 34 percent of Americans report their sleep quality as “poor” or “only fair.”3

More than 50 million Americans have chronic sleep disorders.2

Consequences of Lack of Sleep and Coexisting Conditions

Sleep helps your brain function properly. Not getting enough sleep or poor quality sleep has many potential consequences. The most obvious concerns are fatigue and decreased energy, irritability and problems focusing. The ability to make decisions and your mood can also be affected. Sleep problems often coexist with symptoms of depression or anxiety. Sleep problems can exacerbate depression or anxiety, and depression or anxiety can lead to sleep problems.

Lack of sleep and too much sleep are linked to many chronic health problems, such as heart disease, diabetes and obesity. Sleep disturbances can also be a warning sign for medical and neurological problems, such as congestive heart failure, osteoarthritis and Parkinson’s disease.

Types of Sleep Disorders - Insomnia Disorder

Insomnia, the most common sleep disorder, involves problems getting to sleep or staying asleep. About one-third of adults report some insomnia symptoms, 10 to 15% report problems with functioning during the daytime and 4 to 22% have symptoms severe enough to meet criteria for insomnia disorder. An estimated 40 to 50% of individuals with insomnia also have another mental disorder.1

Symptoms and Diagnosis

To be diagnosed with insomnia disorder, the sleep difficulties must occur at least three nights a week for at least three months and cause significant distress or problems at work, school or other important areas of a person's daily functioning. Not all individuals with sleep disturbances are distressed or have problems with functioning.

To diagnose insomnia, a physician will rule out other sleep disorders (see Related Conditions below), medication side effects, substance misuse, depression and other physical and mental illnesses. Some medications and medical conditions can affect sleep.

A comprehensive assessment for insomnia or other sleep problems may involve a patient history, a physical exam, a sleep diary and clinical testing (a sleep study or polysomnography). A sleep diary is a record of your sleep habits to discuss with your physician. It includes information such as when you go to bed, get to sleep, wake up, get out of bed, take naps, exercise, eat and consume alcohol and caffeinated beverages. In additional, a sleep study allows the physician to identify howlong and how well you are sleeping and to detect specific sleep problems.

Sleep problems can occur at any age but most commonly start in young adulthood. The type of insomnia often varies with age. Problems getting to sleep are more common among young adults. Problems staying asleep are more common among middle-aged and older adults.

Symptoms of insomnia can be:

  • Episodic (with an episode of symptoms lasting one to three months)
  • Persistent (with symptoms lasting three months or more)
  • Recurrent (with two or more episodes within a year)

Symptoms of insomnia can also be brought on by a specific life event or situation.

Treatment and Self-help

Sleep problems can often be improved with regular sleep habits. (See Sleep Hygiene section for tips.) If your sleep problems persist or if they interfere with how you feel or function during the day, you should seek evaluation and treatment by a physician.

Sleep disorders should be specifically addressed regardless of mental or other medical problems that may be present. Chronic insomnia is typically treated with a combination of sleep medications and behavioral techniques, such as cognitive behavior therapy. Several types of medications can be used to treat insomnia and to help you fall asleep or stay asleep. Most of these can become habit-forming and should only be used for short periods and under the care of a physician. Some antidepressants are also used to treat insomnia.

Most over-the-counter sleep medicines contain antihistamines, which are commonly used to treat allergies. They are not addictive, but they can become less effective over time. They may also contribute to confusion, blurred vision, urinary retention, and falls in the elderly and should be used with caution in this population.

Many people turn to complementary health approaches to help with sleep problems. According to the National Institutes of Health some may be safe and effective, others lack evidence to support their effectiveness or raise safety concerns.

  • Relaxation techniques, used before bedtime, can be helpful for insomnia.
  • Melatonin supplements may be helpful for people with some types of insomnia. Long-term safety has not been investigated.
  • Mind and body approaches, such as mindfulness, meditation, yoga, massage therapy and acupuncture lack evidence to show their usefulness, but are generally considered safe.
  • Herbs and dietary supplements have not been shown to be effective for insomnia. There are safety concerns about some, including L-tryptophan and Kava, while others may interact with prescribed medications.

Let your health care provider know about any alternative medicines or supplements you are taking.

Sleep Hygiene: Healthy sleep tips to address sleep problems.

  • Stick to a sleep schedule – same bedtime and wake up time even on the weekends.
  • Allow your body to wind down with a calming activity, such as reading away from bright lights and avoiding electronic devices before sleep.
  • Avoid naps especially in the afternoon.
  • Exercise daily.
  • Pay attention to bedroom environment (quiet, cool and dark is best) and your mattress and pillow (should be comfortable and supportive).
  • Avoid alcohol, caffeine and heavy meals in the evening.

Other Sleep Disorders


  1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR), Fifth edition - Text Rivision. 2022.
  2. Centers for Disease Control and Prevention. Sleep and Sleep Disorders.
  3. National Sleep Foundation. Sleep Health Index. 2017.

Physician Review

Felix Torres, M.D., MBA, FACHE, DFAPA, CCHP-MH

March 2024

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