Sleep Disorders

Updated 15 May 2018

Types of sleeping disorders

It’s estimated one in four people suffer from some form of sleeping disorder – and it affects both their productivity and quality of life.


It’s estimated one in four people suffer from some form of sleeping disorder – and it affects both their productivity and quality of life. The most common sleeping disorders are sleeplessness, sleep apnoea, sleepwalking, sleep terror disorder, restless leg syndrome, periodic limb movement disorder, narcolepsy and REM behaviour disorder.


Sleeplessness (insomnia) is the most common sleeping disorder and most people suffer from it at some point in their lives, says Dr Frans Hugo of the Panorama Psychiatry and Memory Clinic.

Stress, poor diet, hormonal changes, underlying illness or jet lag are the most common causes. Age also plays a role and more women than men struggle with sleeplessness after middle age.

According to Dr Hugo 90 per cent of sleeplessness can be treated without medication. ‘‘I always tell my patients Randy Gardner’s record is 11 days, so you know you’re going to sleep after two weeks because at some stage your sleep debt will be so huge you’ll simply drift off .’’

Good sleep habits are as good as any pill when it comes to conquering insomnia, he says. Sleeping pills are a temporary solution at best because within a few days the brain ‘‘unlearns’’ how to sleep. ‘‘When you’re on medication your sleep ‘architecture’ is different.

You have less REM sleep and your memory patterns are less firmly fixed,’’ Dr Hugo says. Before popping a sleeping pill ask yourself how long you’re planning to take them because some medications – especially benzodiazepam sleeping pills such as Valium – are addictive.

Sleep apnoea

If you believe snoring isn’t dangerous, think again. In some cases it’s a symptom of sleep apnoea, which can be life-threatening.

Sleep apnoea (when you stop breathing for short periods while sleeping) is one of the most undiagnosed medical conditions, Jan Top of the Panorama Sleep Clinic says. ‘‘If you sleep badly, snore heavily and are overweight you should consult your doctor.’’

Sleep apnoea occurs when fat accumulated around the neck, such as a double chin or slackened muscle tissue, flattens the oesophagus during sleep and blocks the flow of air for 10 to 60 seconds. The brain registers a shortage of oxygen; you gasp for air and start breathing again normally. This can happen up to 100 times a night, leaving you tired, irritable and unhappy the next day. You also get headaches because of oxygen deprivation.

‘‘People joke about being woken by their partner’s snoring but sleep apnoea can be lethal,’’ Top says. ‘‘It can cause serious diseases such as diabetes, heart attacks, kidney damage and depression. When you read about people dying peacefully in their sleep it’s often as a result of sleep apnoea.’’

New research shows a second type of sleep apnoea which has nothing to do with obesity and obstruction but is caused by a fault in the breathing control centre of the brain.

Although it can be dangerous it can be treated effectively. Some people stop breathing at night because signals from this centre in the brain don’t reach the muscles used to breathe, Pretoria East Sleep Clinic neurophysiologist Bernard Tjallinks says.

Sleep clinic experts are able to diagnose both types of sleep apnoea and treat them with an apparatus that blows air into the mouth, ensuring continuous oxygen intake. Doctors warn sleep apnoea sufferers not to use sleeping pills or tranquillisers because these drugs could stop them breathing completely.


Sleepwalking (somnambulism) happens during phase four or deep sleep. You get out of bed and do things in your sleep that you’d normally do when you’re awake. It’s difficult to wake you at the time and you can’t remember what happened after the event. Sleepwalkers can injure themselves or others. In America police pulled a driver off the road only to discover the woman had loaded her dogs into the car and driven 40 km – in her sleep!

Sleep terror disorder

Sleep terror disorder (night terrors) typically occur in children and make nightmares seem tame. Parents shouldn’t touch or pick up the child. Switch on a dim light and soothe him in a soft voice until the episode has passed.

Restless leg syndrome

Restless leg syndrome runs in families. It’s an unpleasant itching, prickling or tingling in your legs or feet and you have to move around to get rid of the sensation. Older people especially are affected. It causes sleeplessness and is also linked to anaemia, pregnancy and diabetes. Medicine specifically targeting the neurotransmitter dopamine is effective.

Periodic limb movement disorder (PLMD)

Have you ever been woken in the middle of the night because your bedmate suddenly pulls up both legs, moves his feet or throws his arms and legs wide?

It’s telltale behaviour of someone suffering from PLMD, Peet Vermaak says. It’s the only movement disorder that occurs only during sleep and can vary from repetitive cramps or jerking of the knees, ankles and toes to large movements of all four limbs. Many people who have PLMD don’t realise their legs and feet move suddenly at night and disrupt their sleep; they just feel tired the next day.

The occurrence of PLMD increases with age: almost 50 per cent of people over 65 have it. Treatment with dopamine or sleeping pills can help.


People with narcolepsy have ‘‘nap attacks’’ during the day, irrespective of how they sleep at night. The attacks occur suddenly and can last from a few seconds to about 30 minutes.

Narcolepsy sufferers can also experience catalepsy (loss of muscle control during emotional situations such as a violent argument), hallucinations and temporary paralysis when they wake up. The condition is serious because it can lead to a fatal injury or accident.

Narcolepsy usually runs in families but is sometimes linked to brain injury. It’s usually treated with stimulants or antidepressants.

REM behaviour disorder

It sounds like something from a Halloween horror film but REM behaviour disorder develops when the brain fails to temporarily paralyse the muscles during REM sleep. The result is you literally act out your dreams. Top tells of a patient who knocked herself unconscious by running into a wall at the sleep clinic because she was ‘‘trying to catch a ball’’. ‘‘It’s rare but seeing it is scary and sufferers can seriously injure themselves or others,’’

Top says. In America there have been controversial cases in which sufferers have committed murder or other violent acts because of the disorder. Doctors link it with conditions such as Parkinson’s and brain-stem damage.

(Compiled by Mari Hudson, medical editor Health24, and Elise-Marie Tancred in June 2008.) 


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Dr Alison Bentley is a general practitioner who has consulted in sleep medicine and sleep disorders, in both adults and children of all ages, for almost 30 years. She also researches and publishes on a number of sleep-related topics both in formal research journals and lay publications including as editor of Sleep Matters, an educational newsletter on sleep disorders for doctors.

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