Sleep Disorders: 12 Different Types
Sleep disorders keep about 70 million Americans from getting what mattress commercials say we need most: a needed break from the day’s events. Sleep scientists-men and women who specialize in sleep research-have been able to identify over 80 types of sleep disorders, many of which are related to each other. Since there are so many sleep disorders, we’ll take a look at 12 interesting types!
What are sleep disorders?
Sleep disorders are defined as abnormal conditions that interfere with restful sleep. Disorders in sleep are medically concerning because our body is so highly fueled by a good sleep. Since the time you were born, sleep has been a basic need, just as much as food and water. We are built to get a certain number of sleep hours, depending on the age group, to function both physically and mentally in the day. So with sleep disorders, this function is disturbed to detrimental effect.
The categories of sleep disorders are broad, and there are many different cause-and-effect pathways. Stress and anxiety can factor very much into sleep behavior. In fact, evidence shows sleep disorders are co-morbid with many psychiatric disorders, such as anxiety and depressions.
In some cases, sleep disorders can be genetic, passed on from parent to child. Some disorders are neurological, caused by chemical imbalances in the brain. Other disorders may be inherited from parents. But no matter what the cause, there is really one hallmark of sleep disorders: daytime sleepiness due to a night of abnormal sleeping.
What are the consequences of a lack of sleep? One study estimates that sleep disorders are responsible for over 38,000 cardiovascular deaths a year and cost Americans over a billion dollars a year from accidents, property damage, etc. Never take a good night’s rest for granted!
When were sleep disorders first documented?
The importance of sleep has been well respected in history, as well as the issues surrounding sleep disturbances. Sleep research began in the 1800s and it was two German scientists Westphal and Fisher that reported on narcolepsy: one of the more serious sleep disorders. With more research into sleep, scientists began to identify more and more disorders.
12 Types of sleep disorders
1. Sleep disorders: Insomnia
We all have probably experienced some difficulty sleeping at some point in life. With insomnia, the difficulty can be persistent (chronic insomnia disorder) or fleeting (short-term insomnia disorder). About half of Americans will experience a case of insomnia; 1 in 10 experience chronic problems. There are numerous medical conditions that can lead to insomnia, and in some cases, insomnia can be side effects from medications. When insomnia occurs, people may have trouble falling asleep, wake up during the night, or feel unsatisfied with sleep. Because of this, people affected will report daytime sleepiness, lack of concentration, difficulty in other cognitive skills, irritability or forgetfulness.
2. Sleep disorders: Sleep apnea
Sleep apnea is a disorder in which breathing is irregular during sleep. Breathing will start and stop at different points during the sleep cycle. The most common sign of sleep apnea is loud snoring and gasping for air during sleep. Apnea can be divided into three types:
- Obstructive sleep apnea: this occurs when throat muscles relax and the airway is blocked.
- Central sleep apnea: the airway is not blocked, but occurs the breathing muscles aren’t receiving the neural signals from the brain.
- Complex sleep apnea: a combination of obstructive and central.
Sleep apnea affects people of all ages. But some risk factors include being male, obesity, nasal obstruction, tobacco and alcohol use. Sleep apnea can lead to other health problems, such as stroke, heart failures, and persistent headaches.
Sleep Disorders: Circadian Rhythm Disorders
The body has a sort of internal body clock that regulates our 24-hour sleep and wake cycle. What this means is our body is hardwired to know that the night hours are meant for rest, and the body should awake from slumber at the start of the day. A person with a circadian (Latin for “around the day”) rhythm disorder has a faulty internal body clock that causes them to be in states of wakefulness or sleepiness at the wrong time of day.
3. Sleep disorders: Jet lag disorder
This is a circadian rhythm disorder any experienced traveler will know too well. Jet lag occurs when sleep is interrupted due to rapid (typically airline) travel. Crossing two or more zones is more likely to cause jet lag, and it is only due to eastward or westward travel. Because jet lag manifests during travel, the mechanism is straightforward to deduce: when traveling long distances in short periods, the circadian rhythm is not able to adapt to a new day and night cycle. The body may want to sleep because it is acclimated to the night hours back home, and so jet lag occurs. The exact symptoms of jet lag depend on distance, age, and direction of travel. The common signs are insomnia, stress, and irritability.
4. Sleep disorders: Shift Work Disorder
The “9 to 5” work schedule is one most Americans are comfortable with, but there are employees that need to work outside of that time window. Police officers, hospital workers, and truckers are examples of people who do this type of “shift-work,” and they are the ones most susceptible to shift work disorder.
Shift work disorder causes sleep problems attributed to the lifestyle of being active outside of the natural body cycle. This is one of the disorders that can be directly caused by having to be awake at unconventional hours. Shift work disorder tends to be co-morbid with many issues, including insomnia, irritability, and stomach problems. Also, the lack of socialization because of irregular hours means that people with shift work disorders often report a decreased quality of life. Working irregular hours tends to make those feel isolated from friends and family. If left unchecked there can be a long-term problem due to a lack of regular exercise and poor eating: obesity, cardiac problems, and menstrual irregularities.
Sleep Disorders: Hypersomnia
With this type of sleep disorder, people experience daytime sleeplessness. Unlike with insomnia, hypersomnia is not caused by disorders in the circadian rhythm.
5. Sleep disorders: Narcolepsy (with cataplexy)
Narcolepsy is an unusual disorder that can be attributed to a neurological imbalance. People with narcolepsy may experience daytime sleepiness, but also more serious problems like sleep paralysis or hallucinations. Narcolepsy with cataplexy involves partial loss of muscle control. Cataplexy has been documented to be induced by laughter, which can lead to unfortunate social situations in which people fall to the ground from laughing. Narcolepsy with cataplexy occurs when the brain doesn’t have a chemical called hypocretin. Hypocretin helps regulate sleep and wake cycles. So without it, people will experience dysfunction in regular sleep. In regular sleep, people enter a state of non-rapid eye movement (NREM) which is when brain waves are slowed down. After NREM, we enter REM which is where the majority of dreaming occurs. Without hypocretin, people enter REM sleep immediately. This is may also cause narcoleptic hallucinations, as the body is already in the REM cycle of dreaming.
6. Sleep disorders: Kleine-Levin syndrome
Kleine Levin Syndrome (KLS) is a rare form of hypersomnia that more often affects adolescent males. First diagnosed in 1862, people with KLS will display the usual sleepiness of hypersomnia, but display unusual problems, distinct from narcolepsy. These include cognitive and/or behavioral disturbances, such as confusion, hallucination, or irritability. Another feature is compulsive eating, known as hyperphagia. Increased sexual behavior (hypersexuality) has also been documented, with male patients sometimes committing assault.
Hunger, sex, and sleep behavior are all regulated by a neural pathway called the hypothalamus, so it is believed that some abnormality in the hypothalamus must cause this disorder. However, no definitive cause is known. Imbalances in the neurotransmitters serotonin and dopamine have been reported in KLS patients.
Sleep Disorders: Sleep-related movement disorders.
Sleep-related movement disorders occur when people make repetitive movements during sleep. While tossing and turning in sleep isn’t all that unusual, this type of movement is so pervasive that it will disrupt a person’s sleep or bother the person’s bed partner.
7. Sleep disorders: Restless legs syndrome
Restless legs syndrome (RLS) is also known as Willis-Ekbom disease. People with RLS have urged to move their legs during sleep. Often this is due to an unpleasant experience in the legs. This feeling in the leg can range to mild aching or tingling, to painful burning. This feeling primarily happens during the deep sleep cycle which is why it gets classifies it as a sleep disorder. The constant leg movements cause daytime sleepiness. Primary restless legs syndrome has an unknown cause and can start in early childhood. Secondary restless legs syndrome usually starts after age 45, is more sudden, and has more severe symptoms. Secondary RLS appears to be linked to dysregulation of neurotransmitters such as dopamine and serotonin.
RLS occurs in about 10% of the U.S. population. It tends to be more prominent in pregnant women, with about 20% of women experiencing RLS in their third trimester. The reasons why RLS affect pregnant women are unclear.
8. Sleep disorders: Sleep-related bruxism
Sleep bruxism is the involuntary gnashing or grinding of teeth during sleep. Bruxism can happen while awake, but sleep bruxism is different in that it tends to cause more wear on the teeth. Dental damage from bruxism includes broken teeth, enamel damage, and jaw damage.
Sleep-related bruxism is usually associated with sleep apnea and may be a response to the restriction of airflow. The cause of this sleep disorder may be psychological. Mental disorders such as anxiety may cause bruxism. It’s also known to be associated with people with competitive or hyperactive personality.
Sleep Disorders: Parasomnia
Parasomnia might be considered the most unique of the sleep disorders. Para comes from the Greek root meaning “around” or “alongside,” meaning they occur with sleep, but are not a normal part of the process. Parasomnia can occur at any time during the sleep cycle. Only about 10% of Americans are affected by them. Like most sleep disorders, the sleep disruptions from parasomnia will cause daytime sleepiness.
9. Sleep disorders: Sleep terror
This sleep disorder is also known as night terrors. These go much deeper than a bad dream. People with sleep terrors tend to wake up extremely frightened, sometimes screaming. Factors associated with sleep terrors include stress, fever, and sleep movement disorder restless legs syndrome. Bad dreams happen to us when we sleep. Nightmares are what we usually associated with fear-inducing dreams, but night terrors are a whole beast altogether. Whereas nightmares can usually be vividly recalled, night terrors will induce extreme fear and panic, but cannot be recalled. Nightmares occur during REM sleep whereas night terrors happen during non-REM. Children are likely to experience night terrors, but it usually gets resolved in adulthood.
10. Sleep disorders: Sleepwalking
Sleepwalking, also known as somnambulism (ambulare being Latin for “to walk”) is a disorder characterized by getting up and walking while in a state of sleep. Sleepwalking is more common in children and usually, incidents stop by adolescence. However, there have been cases of adults sleepwalking, and this is usually due to other sleep disorders or an effect of a medication. Overall the prevalence of sleepwalking is between 1% and 15%. We see sleepwalking acting out many times in fiction: characters committing crimes or acting out their deepest subconscious desires for example. The truth is sleepwalkers usually act out by getting out of bed and walking around, nothing more adventurous than that. During this state, people sleepwalking will have a glazed expression, and not easily respond or communicate. There have been cases of sleepwalkers exhibiting more extreme behavior which can include animated talking, screaming (usually in conjunction with sleep terror), or urinating in a different room (more common in children). Some of the more unusual cases have people doing routine activities such as getting dressed, going downstairs, getting the car, etc. In all cases though, sleepwalkers will not recall what happened upon waking up.
If you have heard the cautionary warning that you should not wake a sleepwalker let’s put that to rest: waking a sleepwalker is not dangerous, but should be done carefully. Certainly, waking a sleepwalker will not cause them to get a heart attack or end up comatose. But the waking action should be done gently as to not arouse surprise or panic in the sleepwalker.
11. Sleep disorders: Exploding head syndrome (EHS)
Not as violent as it sounds. The “explosion” in this sleep disorder is the sound that people hear in their heads, preventing them from a good night’s sleep. People have described these sounds like a loud bang, clash of cymbals or a bomb exploding. Although startling, the experience is never described as painful. It does, however, keep people from a restful sleep due to the fear and anxiety it induces, and insomnia and daytime sleepiness is a side effect. This is probably the most unusual of the parasomnias, and the exact prevalence of this disorder is not known. It does appear to be more common in women, and the average age of the first episode is 58 years. The cause of EHS is still being studied: some scientists believe it to be a result of the brain cells misfiring before the body has a chance to fully move out of REM sleep. EHS has been associated with elevated stress levels.
12. Sleep disorders: Sleep paralysis
In many cultures, sleep paralysis was thought to be the work of demons sitting down on the chest of their victims during sleep. This describes the unusual feeling of this sleep disorder: immobilized like they are trapped in bed. For some, this paralysis is accompanied by vivid hallucinations of being attacked, hence the association with demon lore. Sleep paralysis can occur when trying to fall asleep or awaking from sleep. Between 25% to 50% of Americans experience at least one episode of paralysis in a lifetime. Fortunately, it’s not particularly serious. Research suggests that when the body is trying to transition out of the REM (dream) stage of sleep, sometimes it causes the body to seize up. While dreaming, the body doesn’t want to have you act out what’s going on, so it makes sense that the muscles are paralyzed. However, when these effects linger on, that is when the paralysis can occur.
Testing and Treatment for Sleep Disorders
To better understand a sleep disorder, a clinician should get a report from the patient and his/her bed partner, as well as family history. This is accomplished through a series of sleep questionnaires. A patient might also be asked to do a sleep log or sleep diary to calculate things like a number of hours slept, the number of awakenings during the night, and incidents of daytime sleepiness. All of this is very helpful in establishing the type of insomnia (acute or chronic) as well as abnormal behavior that might indicate parasomnia.
Laboratory tests are also a good tool for diagnosis. A patient will usually be asked to be asleep while a clinician performs some lab tests that monitor sleep activity. These could be:
- Polysomnography: measures oxygen levels, body movements, and brain waves.
- Electroencephalogram: Measures electrical activity in the sleeping brain.
- Actigraphy: uses a small portable device to detect physical motion. Usually, a wrist monitor is worn for a period of weeks to monitor wake and sleep hours.
- Genetic blood tests can be used to diagnose narcolepsy and other neurological conditions that cause sleep disorders.
A useful tool for clinicians is to use the International Classification of Sleep Disorders. Published by the American Academy of Sleep Medicine, the ICSD helps to determine the kind of sleep abnormality (circadian rhythm, apnea, etc.)
You might notice that sleep disorders do tend to co-exist in a person, even if they are in different classifications. For example, sleep apnea may be co-morbid with bruxism in some people. Sleep paralysis can be a symptom of narcolepsy. Insomnia is a complication with almost all the sleep disorders.
So with that said, it is difficult to find one treatment for sleep disorders. However, there are three common ways that doctors will treat complications from sleep disorders
- Sleep hygiene: Sleep disorders can often be prevented from practicing good sleeping habits, known as sleep hygiene. Especially for jet lag and even sleepwalking, good sleep hygiene can help regulate the body’s wake-sleep cycles to avoid daytime sleepiness. Sleep hygiene practices include avoiding caffeine and alcohol before bed, trying to head to sleep at a decent hour, and settling into environments conducive to sleep (not looking at bright lights from a computer.)
- Hypnotherapy: the use of hypnosis to treat sleep disorders has been shown to research to work for some cases. During hypnotherapy, patients are put into a trance-like state that makes them more relaxed and open to suggestion. Hypnotherapy has been used to treat sleepwalking and sleep terrors for children.
- Medication: Sleep aids can be a solution to help those with chronic insomnia-most contain an antihistamine to induce sleepiness for those who can’t get to sleep during the night. Melatonin is a hormone drug commonly used for jet lag.
As always, talk to your doctor if you experience sleepiness due to unusual sleeping patterns.
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Nana is a new collaborator for CogniFit. When not writing he works as a University research specialist, focusing on clinical assessment of brain injury. He received his BA from Dartmouth College and recently completed his Master of Public Health degree at the University of Ghana. His MPH dissertation was on cognitive impairment in Africans living with HIV. His interests are in neuropsychology, abnormal psychology, and cognitive disorders. Feel free to provide feedback on the articles he shares.