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June 24, 2022

Get to know the six types of sleep disorders

Get to know the six types of sleep disorders

Sleeping is a matter of health. There is no ‘being healthy’ without ‘sleeping well’. But not everyone can get quality sleep every night – or even sleep at all. A 2020 survey performed by the Ministry of Health found that almost 42% of Brazilians have one or more types of sleep disorders.

Sleep disorder is an umbrella term that refers to a set of conditions and diseases that affect different aspects of a person’s sleep, such as its quality, duration, timing, beginning and continuity. 

Overall, there are more than 100 types of sleep disorders identified worldwide. Some of them are symptoms of other illnesses, while others are the product of a disease. But there are also disorders unrelated to other health issues.

What are the causes of sleep disorders?

Sleep disorders are caused by different factors, some internal (like genetics) and some external (like stress). But even though the causes are different, they all produce the same result: decreased quality of life.

Among the causes for different sleep disorders we can find:

– Medical factors, such as allergies;

– Psychological and psychiatric factors, such as anxiety or depression;

– Physical factors, such as slow metabolism or gastritis;

– Environmental factors, such as heat or consumption of alcohol and caffeine;

– Genetic factors;

– Disruptions of the circadian rhythm;

– Medications (some drugs interfere with sleep);

– Aging.

The 6 types of sleep disorders

The classification that groups them all uses a categorization methodology based on different criteria, among which we can find:

– Causes

– Symptoms

– Psychology

– Psychological consequences

Altogether, there are six types of sleep disorders.

1. Insomnia

Contrary to what many people think, insomnia is not ‘just one thing’, but a ‘box’ of different ‘types of insomnia’. Together, they affect around 73 million Brazilians (data from ABS – Associação Brasileira do Sono).

In the International Classification of Sleep Disorders, insomnias are characterized as ‘a repeated difficulty in onset, duration, consolidation or quality of sleep that occurs despite adequate opportunities and circumstances for sleep, which results in some form of daytime difficulty’.

In short, insomnia can manifest itself in different ways for each person. Most diagnoses, however, fall into two types:

Sleep Onset Insomnia, which refers to difficulty falling asleep.

Sleep Maintenance Insomnia, which refers to difficulty having continuous sleep. It is more common in older people and those who have consumed alcohol, tobacco, or caffeine shortly before going to bed.

Insomnia can still be chronic (appears at least three times a week for a period of three months) or in the short-term (less than three months). 

2. Hypersomnia

Hypersomnia is not a sleep disorder per se, but a symptom of other conditions. The term is used to describe different disorders in which a person sleeps more than usual and/or feels excessively sleepy during the day, damaging their routine. 

Hypersomnias can be primary or secondary:

Primary hypersomnia. Less common, primary hypersomnia sustains itself without other disorders or illnesses that cause excessive sleepiness. For instance, the Kleine-Levin syndrome and Narcolepsy – which affects approximately 3 million people worldwide – are types of hypersomnia.

Secondary hypersomnia occurs as a result of other factors, such as medical conditions, medication, psychiatric disorders, and even other sleep disorders, among others. 

3. Sleep breathing disorders

As the name implies, in sleep breathing disorders there is abnormal breathing during the night. This is the case, for example, of sleep apnea, which affects almost 33% São Paulo’s inhabitants. 

In its International Classification of Sleep Disorders, the American Academy of Sleep Medicine identifies different subtypes of these breathing disorders. They are classified according to their symptoms, causes and forms of treatment.

Obstructive apnea, more commonly known as obstructive sleep apnea, or simply sleep apnea, is a disorder marked by repetitive episodes of airway blockage during sleep, causing lapses in breathing.

Central apnea is characterized by the pause in airflow for a period equal to or greater than 10 seconds during which there is no evidence of respiratory efforts. This can happen when the brain does not send adequate signals to the respiratory muscles or when the muscles stop responding to these stimuli. 

Hypoventilation syndromes, which involve high levels of carbon dioxide in the blood during sleep. This happens due to the lack of air movement in and out of the lungs.

Sleep hypoxemia disorder, characterized by a low oxygen level in the blood during the night. In the hypoxemia disorder, oxygen drops but carbon dioxide does not rise high enough to be characterized as hypoventilation. 

– Snoring, which can be a sign of a bigger health problem. Snoring is the noise produced during sleep and caused by a narrowing of the airways. 

Catathrenia, characterized by deep air inhalation and very slow exhalation, producing a monotonous sound, such as a wheezing or groaning. It does not pose any risk to the patient’s health.

4. Circadian rhythm disorders

The hallmark of circadian rhythm-related sleep disorders is the disruption of the natural circadian cycle, which can cause excessive daytime sleepiness, insomnia, or both. In other words, they are caused by a misalignment between your sleep schedule and the time you should actually be sleeping.

Some of the circadian rhythm disorders are:

Delayed sleep phase, commonly associated with people with an evening and extreme evening chronotypes, who stay up very late and have difficulty waking up early.

Advanced sleep phase, associated with people with morning and extreme morning chronotypes, who have significant difficulties when they need to stay up late. It affects about 1% of middle-aged and older population.

Maladaptation to Shift Work syndrome, related to working hours at inconsistent times, preventing sleep regularity.

Time zone change syndrome (jetlag), which happens when we travel and cross multiple time zones without being able to adapt.

Sleep-wake cycle different from 24 hours disorder, which occurs mainly in blind people, who do not receive natural light signals that tell them when to sleep or wake up. 

5. Parasomnias

Parasomnias are unusual events or experiences during sleep, which represent a middle ground between being awake and falling asleep. They used to be entirely associated with mental pathologies, but modern researchers are already studying their relationship with the brain going in and out of sleep.

There are four types of parasomnia subclassifications:

Non-REM (NREM) sleep parasomnias, characterized by incomplete awakening, poor responsiveness to intervention from others, and limited cognitive functions. Among the NREM sleep parasomnias we can find night terrors, sleepwalking, and sexsomnia. 

REM sleep parasomnias, which occur in the sleep phase where there is rapid eye movement, in this case added to agitated breathing, accelerated heartbeat and increased blood pressure. Among the REM sleep parasomnias are isolated and recurrent sleep paralysis and nightmare disorder.

Talking during sleep or somniloquy, which can happen in both REM and non-REM sleep.

Other parasomnias, which most often occur in the transition period between sleep and awakening, such as nocturnal enuresis (or nocturnal urinary incontinence) and sleep hallucinations.

6. Sleep-related movement disorders

The main characteristic of this type of sleep disorder is abnormal night movements that make it difficult to get quality rest. The consequence of that sleepless night is a less productive day.

Some of the sleep-related movement disorders are:

Restless Legs Syndrome (RLS), characterized by an uncontrollable urge to move the legs, which begin to move involuntarily. With no single defined cause, RLS can get worse over the years. 

Sleep bruxism, a disorder marked by teeth pressing against each other, often making sandpaper motion. The bite of a person with nocturnal bruxism can reach a force equivalent to 115 kg.

Nocturnal cramps are also disorders that fall into this classification.

How is a sleep disorder diagnosed

Each sleep disorder has different diagnostic processes. Some depend on tests such as polysomnography, while others are behavioral.

There is another factor to consider. While some disorders leave clear signs (such as mouth pain generated by bruxism or night urination) and others alarm roommates and housemates (such as snoring or sleepwalking), some disorders can be quite silent and, therefore, even dangerous.

This happens with apnea, for example. It is often confused with excessive snoring and can take a long time to be diagnosed, reducing the patient’s life quality for a considerable time. 

Meanwhile, narcolepsy goes undiagnosed in 75% of cases, as estimated by the Narcolepsy Network, an American organization founded in 1986.

So, how do I know if I have one or more of these types of sleep disorders? If you feel like you don’t sleep well often, feel very sleepy during the day or feel that your quality of life is decreasing and sleep plays a role in this, talk to your doctor.

By the way, always discuss your sleep with your doctor. Sleep is health. Sleep is life.

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