Sleep disorders

Causes of sleep disorders

The actual causes of many sleep disorders are not fully understood however there is growing evidence which suggests certain factors can lead to problems with sleep. There are a number of different types of sleep disorder and the main ones are listed below.

Sleep apnoea
Sleep apnoea refers to conditions that restrict airflow through the upper airway while asleep. The sound created by this problem is known as 'snoring' which is the vibration of soft tissue in the nose, mouth and throat.

Common causes of sleep apnoea include:

• being overweight or obese
• nasal congestion (e.g. from a cold)
• abnormal jaw position or nasal cavities
• hypothyroidism
• enlarged tonsils
• enlarged adenoids

When breathing is completely disrupted during sleep the condition is known as obstructive sleep apnoea. Central sleep apnoea refers to a condition which affects the brain's ability to stimulate breathing while asleep. The common reason for this is heart failure or problems with the central nervous system.

Insomnia
There are many causes for insomnia and it is the most common of all the sleep disorders. Insomnia causes difficulty with getting to sleep or staying asleep.

Insomnia can be caused by:

• Stress
• Depression
• Stimulants (e.g. caffeine)
• Medications
• Drug or alcohol use
• Bad sleeping habits (such as watching television in bed)
  
  

Parasomnias
This is an umbrella term for sleep disorders such as sleepwalking, night terrors, sleep paralysis or REM behaviour disorders (whereby the individual acts out their dreams). Causes of parasomnias include psychiatric problems, drug use or certain medical conditions such as Parkinson's disease.

Restless Legs Syndrome
This tends to be a hereditary condition (runs in families) although secondary problems such as iron deficiency, diabetes mellitus, rheumatism, pregnancy, MS or Parkinson's disease can also cause the syndrome.

Circadian Rhythm Disorders
The circadian rhythm is the natural sleep-wake cycle that most people experience (waking on daylight and sleeping during the night). However, people who work shift patterns or have travelled across time-zones can have this cycle disrupted. People who are blind may have circadian rhythm problems.

Narcolepsy
The three potential causes of narcolepsy are a loss of neurotransmitting signals, genetic factors or rare lesions on the brain.

Symptoms of sleep disorders

The different types of sleep disorders have certain characteristics which define them but the common symptom for all is a disruption to natural sleep. The common sleep disorders and their symptoms are listed below.

• Sleep apnoea – interrupted sleep caused by the windpipe closing. Symptoms include snoring, gasping for air, morning headaches.
• Insomnia – inability to fall asleep or stay asleep. Feeling tired during the day and worrying about not getting enough sleep. Judgement can become impaired and a person may also experience drowsiness, poor memory and lowered immunity.
• Parasomnias – sleep paralysis results in an inability to move the limbs which causes distress and anxiety on waking. Night terrors differ from nightmares in that they can not be recalled on waking. A person might scream when they wake and experience excessive sweating and increased heart rate. Night terrors can also cause someone to sleepwalk.
• Restless leg syndrome – the symptoms include a prickly or tingling sensation in the legs causing a person to move their legs for relief. The jerking movements can occur up to three times a minute.
• Circadian rhythm disorders – reduced or unnatural sleep can have associated physical symptoms such as fatigue and poor concentration as well as psychological effects such as mood problems, stress and anxiety.
• Narcolepsy -  the main symptom of narcolepsy is falling asleep uncontrollably during the day. This can last anywhere from a minute to half an hour and occur at any time.

Diagnosis of sleep disorders

It is important to seek a medical diagnosis for sleep problems as insufficient sleep can have a significant detrimental effect on physical and mental wellbeing.

In the first instance, you should visit your GP who will assess you for any underlying conditions which may be causing the problem. If necessary, you will be referred to a specialist for further testing.

Related Terms

Sleeplessness
Night
Bed
REM
Dyssomnias
Parasomnias
Nightmares