What are the most common sleep disorders?

Sleep disorders include a variety of conditions that impact sleep quality and quantity. They can affect someone’s daily function while awake, and may be symptoms of and/or contribute to other physical or mental health issues.


Today, more than 100 specific sleep disorders are recognized by the medical community. But, most of them fall into one of these four main categories:

• Having trouble falling and staying asleep at night
• Having trouble staying awake during the day
• Inability to keep a regular sleep schedule
• Sleep-disruptive behaviors

In this article, we’ll cover five of the most common sleep disorders.


Insomnia causes people to have difficulty sleeping, despite their best efforts to do so. There are three types of insomnia:

Sleep-onset insomnia

Makes it difficult for people to fall asleep even though they feel tired.

Sleep maintenance insomnia

Makes it difficult to stay asleep for the whole night. Specifically, if someone with this type of insomnia wakes for any reason throughout the night, they will have a hard time falling back asleep.

Mixed insomnia

Sufferers exhibit both of the previous types of insomnia and can have a difficult time with both falling asleep and staying asleep.

Since people with insomnia tend to not get enough sleep during the night, they often feel very sleepy during the day and can experience cognitive impairments. Insomnia is classified as chronic when someone experiences symptoms three or more times per week for at least three months.

Statistics show that as many as 33% of adults suffer from insomnia. Fortunately, there are several ways to help alleviate insomnia, including light therapy, cognitive behavior therapy specifically for insomnia (CBT-I), exercise, meditation and other relaxation techniques, medication, and sleep hypnosis.


Hypersomnia can cause constant and recurring feelings of extreme tiredness during the day, despite many people with hypersomnia sleeping 10 or more hours per night. They can have difficulty waking up in the morning or after daytime naps, and can sometimes become confused or even aggressive upon waking. Daytime naps don’t tend to relieve sleepiness or improve levels of alertness. Sufferers can also experience anxiety, irritability, restlessness, inability to focus, slow thinking and speech, headache, loss of appetite, and hallucinations.

Hypersomnia can be caused by other medical conditions, such as epilepsy, tumors, encephalitis, obesity, and Parkinson’s disease. Certain mental health conditions can also cause it, including seasonal affective disorder, bipolar disorder, and depression. Medication and alcohol use can lead to hypersomnia.

Narcolepsy, which we’ll cover next, is a type of hypersomnia, although hypersomnia can also be idiopathic—meaning no specific condition or reason can be identified as the cause.


Narcolepsy causes people to feel extremely tired during the day, even if they have gotten plenty of sleep the night before. It can cause “sleep attacks” where people spontaneously fall asleep for a few minutes at a time throughout the day. Those with narcolepsy can also experience automatic behaviors while they are technically asleep, disruptions to nighttime sleep, sleep paralysis, and sleep-related hallucinations.

There are two types of narcolepsy: type one (NT1) and type two (NT2). NT1 is associated with cataplexy (a sudden loss of muscle control) and low levels of hypocretin-1 (a chemical that helps control sleep and wakefulness). Those with NT2 do not have cataplexy or low hypocretin-1 levels, although they can eventually develop those symptoms and be reclassified as NT1. 

Narcolepsy can significantly impact day-to-day life as everyday tasks such as driving and navigating stairs can be very dangerous when you might fall asleep and lose control of your body at any time. Medicine and behavioral adaptations can help manage symptoms, although there is no cure for narcolepsy and no treatment can completely eliminate all symptoms.

Non-24-Hour Sleep-Wake Disorder

Most people’s circadian rhythms operate on a 24-hour basis, but some people experience shorter or longer than usual sleep-wake cycles. For most of us, environmental cues like the sun rising and setting help our brains and bodies stay synchronized to a 24-hour cycle. However, some people do not have this intrinsic clock.

Non-24-hour sleep-wake disorder (N24SWD) is most prevalent in people who are completely blind, since light-based cues cannot be perceived. In fact, nearly half of those with total blindness have N24SWD. However, sighted people can be affected by this sleep disorder as well, although it can easily be misdiagnosed.

Some treatments can help with N24SWD, although it so far appears to be a lifelong disorder. Medications like melatonin supplements and melatonin receptor agonists are typically taken at a certain time in advance of a person’s desired bedtime in order to help trigger sleep on time. Bright light therapy in the mornings can also be an effective treatment for sighted people or those who are partially blind but can still detect light.

Sleep Apnea

Sleep apnea is a disorder that makes it difficult to breathe while sleeping. It causes people to wake up choking or gasping, and can also cause serious snoring. Since sufferers are often woken by the condition multiple times throughout the night, they can also experience daytime fatigue and sleepiness as well as headaches and cognitive impairment from chronic lack of sleep. 

There are two types of sleep apnea:

Obstructive sleep apnea

OSA is caused by a physical obstruction in the upper airway or throat. This can include especially large adenoids or tonsils, fluid buildup, genetic facial structure differences (such as cleft palate), or fat deposits. Obesity is often a cause of obstructive sleep apnea. Additionally, sleeping on your back can allow your tongue to fall to the back of your throat and block your airway.

Central sleep apnea

With CSA, the brain temporarily stops sending signals to the muscles that control breathing, resulting in the cessation of normal breathing. This type of sleep apnea can be caused by problems with the brainstem, which may be caused by stroke, brain infection, or neck injuries. Narcotic painkillers can also cause CSA.

Some people can suffer from both types of sleep apnea at once. Fortunately, both OSA and CSA can often be treated effectively with continuous positive air pressure (CPAP) therapy. However, some find that bi-level positive air pressure (BiPAP) therapy is more effective for CSA specifically.



Written by

Cat Caroll

Articulate Writer and Analytical Editor

Copyright © Neybox Digital Ltd.