Sleep disorders

Diagnosis

Dyssomnias

Both transient and chronic insomnia are characterised by symptoms that include daytime sleepiness, irritability, impaired memory and concentration, and headaches. Their main difference is in their duration: insomnia is defined as being transient if the disturbance in sleep lasts less than 4 weeks, whereas chronic insomnia is insomnia which lasts for longer than 4 weeks.

The hypersomnias have similar characteristics to the insomnias. In addition to these symptoms, people with apnoea or narcolepsy have an excessive, constant, undesirable sleepiness during waking hours. People with narcolepsy may also experience cataplexy, sleep paralysis and hypnagogic hallucinations, and people with apnoea experience a cessation of breathing which causes them to wake up.

The main sign of circadian rhythm sleep disorders is sleeping at abnormal times compared with what is socially accepted as normal. Jet lag and shift work sleep disorder can produce insomnia at night. In addition, jet lag can cause gastrointestinal discomfort. The main symptom of delayed sleep phase syndrome (DSPS) is difficulty waking at the desired time and, conversely, people with advanced sleep phase syndrome (ASPS) experience sleepiness during the early evening hours, but find it difficult to sleep beyond 2-4am.

Parasomnias

Both sleepwalking and sleep terrors have clearly recognisable, dramatic symptoms. The main signs of sleepwalking are walking sedately with open eyes, and having an unsteady, ataxic gait. The main signs of sleep terrors are sitting upright, screaming, having a wide-eyed stare and dilated pupils, breathing rapidly, sweating and having a high pulse rate.