Most sleep specialists and doctors will use one of two major systems to diagnose a specific sleep disorder:
- The Diagnostic and Statistical Manual of Mental Disorders (DSM)
- The International Classification of Sleep Disorders (ICSD)
The International Classification of Sleep Disorders (ICSD) is the primary diagnostic manual for most sleep researchers and doctors worldwide. It’s a combined effort from the American Academy of Sleep Medicine and the European, Japanese and Latin American sleep research societies.
In 2014, the latest edition of the manual was released – the ICSD-3. Perhaps the most notable change is that there are now 6 main categories of sleep disorder instead of 4.
This list covers the most common types of sleep disorders, as well as some of the interesting and rare sub-types.
In the ICSD-s, insomnia also underwent some major changes, for example removing the long-standing concept of primary and secondary insomnia.
Insomnia is defined in the manual as:
…a persistent difficulty with sleep initiation, duration, consolidation, or quality that occurs despite adequate opportunity and circumstances for sleep, and results in some form of daytime impairment
2. Sleep related breathing disorders
Snoring is a very common problem, with an estimated 40-45% of adults snoring. And many more may be affected by the snoring of their partner or family members.
It doesn’t necessarily mean that you have a sleep disorder just because you snore though; the extent to which it affects your breathing and quality of sleep determines how serious the problem is.
Sleep apnea is a sleep disorder involving a person having pauses in their breathing, or breathing shallowly. The pauses, known as Apneas, can last for between a few seconds and minutes. Often a person will resume breathing again with a noise like a snore, choke or gasp.
Many people are unaware they suffer from sleep apnea. It’s often someone else, such as a partner, who first notices the problem.
People with sleep apnea often experience poor quality sleep because of it. They also often become accustomed to the on-going excessive daytime tiredness which accompanies it.
There are two main types of sleep apnea – obstructive sleep apnea and central sleep apnea.
Catathrenia (nocturnal groaning)
Catathrenia is thought to be quite rare, with no definitive treatment. The nocturnal groaner will emit a loud noise when exhaling, but it’s not to be confused with other disorders such as snoring or apnea.
It doesn’t tend to wake the person up, though anyone else sleeping nearby might be disturbed. And in some cases the noise can sound quite inappropriate.
Management of the problem is usually based on helping anyone nearby deal with the noise.
3. Central Disorders of Hypersomnolence
Hypersomnia is characterized by excessive sleepiness and daytime sleepiness, as well as difficulty in waking up in the morning even after a good long sleep.
Sufferers of hypersomnia may experience confusional arousals, also known as ‘sleep drunkenness’ (see below). This means they will feel very disorientated upon waking up.
Narcolepsy is the best known sleep disorder of this type. It’s caused by a defect in a part of the brain. The result is excessive daytime sleepiness, and actually falling asleep during the daytime.
These episodes of falling asleep often occur at very unwanted moments, such as in the middle of a conversation.
People who have narcolepsy may also experience sudden muscle relaxation or collapse (cataplexy). Sometimes this is preceded by emotional reactions like laughter or fear.
Other symptoms include sleep paralysis and hypnagogic hallucinations.
Kleine-Levin syndrome is a very rare sleep disorder. It involves a person having periods when they are asleep most of the day and night. This can last for days, weeks or even more. In between these periods are usually times when they are completely normal.
Someone with this sleep disorder will wake up for short moments during sleepy periods to use the toilet or eat.
Their behavior during these waking moment is often quite unusual though. They may be disorientated or eat excessively for example. And they may show lacks of inhibition – sometimes sexually in men.
Excessive daytime sleepiness (EDS)
Excessive daytime sleepiness is also perhaps best seen as a symptom rather than a sleep disorder. It isn’t the same as feeling tired because of a bad night’s sleep.
Sufferers are often seen as being lazy, bored or not making an effort, and they rarely seek medical help for this. It can have serious effects on a person’s day-to-day life and functioning though.
Excessive daytime sleepiness usually involves one or more of the following:
- Feeling tired and lacking energy
- Falling asleep during the day
- Needing to sleep a lot at night and struggling to get up
- Feeling the need to nap frequently during the day
4. Circadian Rhythm Sleep-Wake Disorders
Circadian rhythm disorders are a type of sleep disorder that involve disruption to your internal body clock. These types are often confused with insomnia, so it’s important to understand the distinction between them and insomnia.
The disorders below can be treated by either gradually retraining your sleep time, with melatonin supplements or light therapy.
Delayed Sleep Phase Syndrome (DSPS)
Delayed Sleep Phase Syndrome often develops at a young age, such as in the teenage years. Someone with DSPS goes to sleep later and wakes up later. They end up being out of sync with the normal hours of other people, or with the rhythm they actually want.
It may be seen by some people as normal teenager behavior. But a problem arises when someone cannot fall asleep and wake up when they would need to.
Their quality of sleep might be fine though – just the timings are out. This out-of-sync pattern can also develop due to shift work or jet-lag.
Advanced Sleep Phase Syndrome (ASPS)
Advanced Sleep Phase Syndrome can be seen as the opposite of Delayed Sleep Phase Syndrome. It’s when a person falls asleep early and wakes up early.
It’s also more common in older people, who may find it very hard to stay awake in the evening, but wake up very early in the morning.
When you travel across time zones, you can become out of sync with the natural cycle of daylight. This can result in you not being able to sleep at the local time, nor wake up at the time you would want to.
Jet Lag can take several days to overcome, but there are steps that can be taken before, during and after traveling to reduce the impact.
They often occur during childhood, but can sometimes continue into or start in the adult years.
Some of the following are known as ‘arousal disorders’ and are the most common forms of parasomnia. For example sleepwalking, sleep terrors and confusional arousals.
They are when someone partially arouses from deeper sleep. It then appears that they are both asleep and awake due to their behavior.
Sleepwalking (also known as Somnambulism) can result in a wide range of behavior. Some people may get up and calmly carry out simple tasks.
Others may behave in strange ways. And a rare few may engage in aggressive or destructive behavior. A person may even do something worryingly complex like drive their car.
It is also possible they may accidentally injure themselves or others while sleep walking. This is one reason that certain sleeping pills like ambien carry warnings of these types of risks.
Confusional arousals are when a person wakes up in the night in a state of disorientation or confusion. It’s usually a mild event and so they fall asleep again easily.
It’s most common in children, though does occur in adults also. There isn’t usually the same complex behavior seen as with sleep walking for example, but the person may still sit up or do basic tasks like turn a lamp on, and even stumble around the bedroom.
This is why the disorder is sometimes called sleep drunkenness. In some extreme cases they may behave in a way that’s dangerous to themselves or others.
Sleep terrors, sometimes called night terrors, occur during the non-rapid eye movement sleep stages 3 and 4. They can be upsetting to observe because the person, usually a child, is in such a high state of agitation or fear.
They will not normally remember anything that happened during an episode if they wake up. And they will usually calm down naturally while still asleep.
Nightmares occur during the Rapid Eye Movement stage of sleep. They will usually wake a person up, often with a vivid memory of a frightening or distressing dream.
The person is usually very alert on waking with the ability to recall the dream clearly. They may need calming down to fall asleep again.
Sleep talking, or somniloquy, involves talking during your sleep without being aware of it. It can range from conversational content to mumbling or nonsense. Usually no treatment is required unless it becomes a persistent nuisance.
REM Sleep Behavior Disorder (RBD)
Rapid eye movement behavior disorder involves a person acting out their dreams in their sleep.
A person with RBD does not experience the muscle paralysis that comes with the REM stage of sleep. They are therefore able to move their limbs, talk or act out actions from their dreams.
This can be problematic because of the risk of causing an injury while enacting a dream.
Bedwetting (or nocturnal enuresis) usually occurs during childhood. It occurs either because they haven’t yet learned bladder control, or they have lost bladder control at some point.
If it begins in adulthood, it’s caused by another medical condition or sleep disorder.
Many people will experience sleep paralysis at least once in their lifetime. It involves the sensation of not being able to move or talk, either when falling asleep or waking up.
It’s usually accompanied by hallucinations – such as of a demon or other presence often interpreted as scary or evil. And some people may have an out-of-body experience. It can be extremely disturbing to experience even though it’s harmless.
Exploding Head Syndrome
Exploding head syndrome fortunately doesn’t involve any physical pain or damage, despite the scary name. The sufferer will experience a very loud noise inside their head. It could seem like a gunshot, bomb, shouting, or any other loud sound.
It can be quite disturbing and upsetting for the person, and there is no treatment at the moment. Though it is associated with stress and tiredness, so reducing those factors can help.
6. Sleep related movement disorders
Periodic limb movement disorder is not to be confused with restless legs syndrome (RLS), even though many people experience both.
Periodic limb movement disorder is when a person moves, jerks or flails their limbs during sleep. It’s usually the legs which move, but sometimes the arms also.
This may not wake them up, but it can disrupt their quality of sleep – resulting in daytime sleepiness. Often it’s a partner who is more aware of the problem.
This should also not be confused with the normal movements that many people make while falling asleep.
For example the hypnic jerk – when you feel a jolting movement when dropping off to sleep. Periodic Limb movement disorder can be similar, but continue through the night.
Restless Legs Syndrome (RLS)
Restless legs syndrome is a sleep disorder which can occur during the daytime while a person is awake. However, the symptoms are usually worse in the evening and at night. This can make is hard for someone to fall asleep and stay asleep.
It’s characterized by an often irresistible urge to move the legs (or arms sometimes). This is often accompanied by intense feelings of discomfort. For example tingling, burning, itching, cramping or even skin crawling sensations.
Many people find they can relieve the symptoms by moving, exercising, massaging or bathing their legs.
Bruxism – teeth grinding
Bruxism affects around 8% of people and is characterized by the clenching or grinding of teeth throughout the night.
It can result in people needing dental work, having headaches, jaw and facial pain. It can lead to them disturbing their own sleep, and their partner’s due to the noise.
It’s common with people suffering from Apnea, coffee and alcohol drinkers, and smokers. It may also be associated with stress and anxiety.
Hypnic Jerks – Sleep Starts
Like many people, you may experience the occasional hypnic jerk while falling asleep. This is a sudden jolting of the body, which usually wakes you up.
It may feel like falling or spasming. It can be distressing, but usually doesn’t mean there’s anything wrong with you.
Understanding the different types of sleep disorders
As stated at the beginning, this isn’t a complete list of sleep disorders. But hopefully you’ll now have a better understanding of the different types of sleep disorders that exist.
It can be confusing when researching sleep disorders on the internet, mainly because different websites may be working from different classification systems – or not at all.
This means that you may find one website gives a different description of a sleep disorder to another one. Or that the names suddenly change from one place to the next.
You may also find that one source puts a particular disorder under one category, but another source puts it under a completely different category.
The main thing to bear in mind then is to not get too caught up in the categories themselves. Try to focus on the disorder which interests you.
Most importantly, speak to your doctor if you think you may have a sleep disorder. Some can be serious if left untreated, so you need to be sure you receive a professional diagnosis, guidance and treatment plan.
You can also of course educate yourself, but be careful not to rely solely on self-diagnosis and treatment.