The Various Types Of Sleep Disorders

Written by Kevin Morton, with medical descriptions from The Stanford Sleep Book

There are currently over 80 different types of sleep disorders listed in the International Classification of Sleep Disorders (or ICSD), the latest edition of which was published in 2005.

This is fantastic evidence of how far we've come in the field of sleep medicine in the last handful of decades; however, the fact that an enormous number of people who actually have these various types of sleep disorders are not diagnosed and live without treatment goes to show how very far we still have left to go.

Sleep medicine hasn't yet permeated the medical school curriculum to any significant degree, so there's a large discrepancy between the knowledge that exists about sleep medicine and what most general physicians know about it. As a result, many types of sleep disorders go undiagnosed, mistaken for other ailments whose symptoms may be caused by the sleep disorder.

This highlights the important role that sleep specialists play in society's overall health, but also the extraordinary importance of widespread public knowledge about the types of sleep disorders and their symptoms. If you know how certain sleep disorders make themselves apparent and affect waking life, you will be well-equipped to catch them in yourself and your loved ones.

What Dr. Dement highlights above really goes to show that the general public, you and me, would be doing themselves a great favor if they didn't have to be dependent solely on doctors when it comes to sleep health. Sleep medicine is still working its way into the field. So in the meantime, if we educate ourselves we can avoid the debilitating and sometimes fatal consequences of sleep disorders, being ready to consult a sleep specialist when the need arises.

That said, let's get started!

Sleep disorders can be categorized into two main categories--dyssomnias and parasomnias. (There is also a third tangential category that relates to other conditions, such as depression and alcoholism, and we'll cover this below as well.)

Dyssomnias

Dyssomnias are disorders that produce either excessive sleepiness or difficulty in initiating or maintaing sleep. Some of the most common dyssomnias include obstructive sleep apnea, restless legs syndrome, and conditions of the biological clock such as shift work sleep disorder, and delayed sleep phase syndrome.

Dyssomnias can additionally be divided up into three sub-categories: Intrinsic Sleep Disorders, Extrinsic Sleep Disorders, and Circadian Rhythm Sleep Disorders. Let's look below to see how the various types of sleep disorders fit in.

A. Intrinsic Sleep Disorders

1. Psychophysiological Insomnia
2. Sleep State Misperception
3. Idiopathic Insomnia - Basically a lifelong inability to obtain adequate sleep, presumably due to an abnormality of the neurological control of the sleep-wake system.
One of the most common and dangerous dyssomnias, obstructive sleep apnea, is treated using this continuous positive airway pressure (or CPAP) machine.
4. Narcolepsy
5. Recurrent Hypersomnia - This rare condition is characterized by repeated episodes of too much sleep, typically weeks or months apart. The best known form is Kleine-Levin syndrome (more colloquially known as the Sleeping Beauty syndrome).
6. Idiopathic Hypersomnia
7. Posttraumatic Hypersomnia
8. Obstructive Sleep Apnea Syndrome
9. Central Sleep Apnea Syndrome
10. Central Alveolar Hypoventilation Syndrome
11. Periodic Limb Movement Disorder
12. Restless Legs Syndrome

B. Extrinsic Sleep Disorders

1. Inadequate Sleep Hygiene
2. Environmental Sleep Disorder
3. Altitude Insomnia
4. Adjustment Sleep Disorder
5. Insufficient Sleep Disorder
6. Limit-Setting Sleep Disorder - Primarily a childhood issue, limit-setting sleep disorder is characterized by the inadequate enforcement of bedtimes by a caretaker with the patient then stalling or refusing to go to bed at a time conducive to good health.
7. Sleep-Onset Association Disorder
8. Food Allergy Insomnia
9. Nocturnal Eating (Drinking) Syndrome
10. Hypnotic-Dependent Sleep Disorder
11. Stimulant-Dependent Sleep Disorder
12. Alcohol-Dependent Sleep Disorder
13. Toxin-Induced Sleep Disorder

C. Circadian Rhythm Sleep Disorders

1. Time Zone Change (Jet Lag) Syndrome
2. Shift Work Sleep Disorder
3. Irregular Sleep-Wake Pattern
4. Delayed Sleep Phase Syndrome
5. Advanced Sleep Phase Syndrome
6. Non-24-Hour Sleep-Wake Disorder

Parasomnias (Learn more about parasomnias)

Unlike dyssomnias, parasomnias are clinical disorders that are not abnormalities of the processes that govern our sleep/wake states (processes such as our biological clock, for example). Instead, parasomnias consist mainly of inappropriate physical behaviors that intrude predominantly during sleep.

When you think of parasomnias, "physical" is a key word. Think of examples such as sleepwalking, sleep starts, bruxism, and bedwetting (or sleep enuresis, as it's technically called), which all involve some sort of specific action or movement. This is not an overarching rule, but just something to help you remember the majority of parasomnias by (note too that parasomnia and physical both start with the letter p). Other disturbances that encroach into sleep, such as nightmares, also fall under the category of parasomnias.

Furthermore, parasomnias can be divided up into four sub-categories: Arousal Disorders, Sleep-Wake Transition Disorders, Parasomnias Usually Associated With REM Sleep, and an "Others" category. Let's take a look at where the various types of parasomnias pan out:

A. Arousal Disorders

1. Confusional Arousals
2. Sleepwalking (Somnambulism)
3. Sleep Terrors (Pavor Nocturnus)

Really severe arousal disorders have even been known to bring about violence during sleep, sometimes resulting in deaths and court hearings. You can learn more about sleep-related violence and the trials that follow here.

B. Sleep-Wake Transition Disorders

1. Rhythmic Movement Disorder
2. Sleep Starts
3. Sleep Talking (Somniloquy)
4. Nocturnal Leg Cramps

C. Parasomnias Usually Associated With REM Sleep

1. Nightmares
2. Sleep Paralysis
3. Impaired Sleep-Related Penile Erections
4. Sleep-Related Painful Erections
5. REM Sleep-Related Sinus Arrest - A cardiac rhythm disorder that is characterized by sinus arrest (a pause in the cardiac rhythms) during REM sleep in otherwise healthy individuals. EKG monitoring demonstrates periods of asystole (a lack of contractions of the heart) during sleep that may last up to nine seconds! These periods of asystole occur repeatedly during REM sleep and as you can imagine, are very alarming and dangerous. They also are not associated with either sleep apnea nor sleep disruption.
6. REM Sleep Behavior Disorder

D. Other Parasomnias

1. Sleep Bruxism - Tooth grinding
2. Sleep Enuresis
3. Sleep-Related Abnormal Swallowing Syndrome - A disorder in which inadequate swallowing of saliva results in aspiration (inhalation) of excess saliva, with coughing, choking, and brief arousals or full awakenings from sleep.
4. Nocturnal Paroxysmal Dystonia
5. Sudden Unexplained Nocturnal Death Syndrome (SUND) - SUND is characterized by sudden death during sleep in healthy young adults, particularly of Southeast Asian descent. Neither clinical history nor autopsy results provide an explanation for the cause of death--it remains a mystery. According to witnesses of SUND though, the first signs are choking, gasping, and labored respiration.
6. Primary Snoring
7. Infant Sleep Apnea
8. Congenital Central Hypoventilation Syndrome
9. Sudden Infant Death Syndrome (SIDS) - SIDS is unexpected sudden death of infants in which a thorough postmortem investigation fails to demonstrate an adequate cause for death. At least 80% of SIDS deaths occur at a time when infants were assumed to be asleep. It has not been unequivocally established whether the primary cause of death is cardiac or respiratory failure.
10. Benign Neonatal Sleep Myoclonus

Sleep Disorders Associated With Medical/Psychiatric Disorders

Most mental or mood disorders can have some sort of sleep disturbance that typically comes along with it to affect the patient. The ICSD includes various psychoses, mood disorders, anxiety disorders, panic disorders, and alcoholism in its list of sleep disorders because they are commonly seen in patients who present sleep complaints, and thus need to be considered to paint the full diagnosis picture.

This category of sleep disorders associated with other medical disorders is also broken up into three sub-categories: Mental Disorders, Neurological Disorders, and other Medical Disorders. The disorders that fall within each category are listed below.

A. Associated with Mental Disorders

1. Psychoses
2. Mood Disorders
3. Anxiety Disorders
4. Panic Disorders
5. Alcoholism

B. Associated with Neurological Disorders

1. Cerebral Degenerative Disorders
2. Dementia
3. Parkinsonism - Refers to a group of neurologic disorders characterized by hypokinesia, tremor, and muscular rigidity. Insomnia is the most common sleep-related symptom in patients with parkinsonism.
4. Fatal Familial Insomnia - A progressive disorder that begins with difficulty in initiating sleep and leads to total lack of sleep within a few months and, later, to spontaneous lapses from quiet wakefulness into a comatose state with enacted dreams.
5. Sleep-Related Epilepsy
6. Electrical Status Epilepticus of Sleep
7. Sleep-Related Headaches - Sleep-related cluster headaches, chronic paroxysmal hemicrania, and migraines are severe, mainly unilateral headaches that often have their onset during sleep. The patient is either awakened with pain during the night or is aware of an attack upon awakening in the morning.

C. Associated with Other Medical Disorders

1. Sleeping Sickness
2. Nocturnal Cardiac Ischemia
3. Chronic Obstructive Pulmonary Disease (COPD) - Characterized by a chronic impairment of airflow through the respiratory tract between the atmosphere and the gas-exchange portion of the lung. Altered cardiorespiratory physiology during sleep or a complaint of insomnia can occur.
4. Sleep-Related Asthma
5. Sleep-Related Gastroesophageal Reflux
6. Peptic Ulcer Disease
7. Fibromyalgia - Characterized by diffuse musculoskeletal pain, chronic fatigue, unrefreshing sleep, and increased tenderness in specific localized anatomic regions, without laboraty evidence of contributing articular (joint), nonarticular, or metabolic disease.

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