Insomnia is a sleep disorder that affects a person’s ability to fall asleep or stay asleep for long enough to feel replenished the following day. The resulting tiredness can affect a person’s quality of life, making it difficult to concentrate or function as usual during the day.

Insomnia is thought to affect around a third of individuals in the U.K at some point in their lives. Women are more likely to develop the condition than men and it is also more likely to occur with increasing age.

Insomnia is classed as either primary or secondary. Primary insomnia has no obvious cause, whereas secondary insomnia arises as a result of another underlying health condition. Insomnia is also described as acute or chronic. Acute insomnia is short term and may last anything from one night to four weeks, while chronic insomnia is defined as insomnia that occurs for at least three nights per week for a month or longer.

Symptoms

The symptoms of insomnia can vary significantly from person to person. Some people may develop severe symptoms and be unable to fall asleep at all for long periods of time, while others may fall and stay asleep for the duration of the night, but not feel refreshed when they wake. Often, people suffer from problems during the day as a result of difficulty focusing or being able to stay awake. Typical symptoms of insomnia are described in more detail below.

Difficulty falling asleep

People affected by insomnia may lie in bed for hours, but find they are unable to fall asleep. This problem can last for long periods, leading to severe sleep deprivation that has a very negative impact on daily life.

Waking during the night

Sometimes, people with this condition do manage to fall asleep, but then wake up frequently throughout the night. This inability to sleep through the night can mean people wake up without feel properly rested and refreshed, which can also lead to problems in the day.

Waking early

Some people may be able to fall asleep and stay asleep for a period of time but then wake up in the early hours of the morning, at 3 or 4 am, for example. They may wake feeling extremely tired or exhausted, but still not be able to drift back off to sleep.

Not feeling rested

Some individuals do manage to sleep through the night, but do not feel refreshed on waking up the following morning. This is often due to their sleep only being a light or to sleep disturbances that disrupt the stages of sleep needed for adequate rest.

Sleepiness in the daytime

People affected by insomnia often find they feel exhausted and sleepy throughout the day. They may rely on a high caffeine intake to keep them awake throughout the day. However, increasing the intake of this stimulant only worsens the sleep problems already being experienced during the night. Individuals with insomnia should avoid drinking caffeinated drinks or any other substance that might disrupt sleep.

Difficulty focusing on tasks

Insomnia can decrease mental function and lead to problems thinking, concentrating, or paying attention. This can have a huge negative impact on people’s performance at work or school.

Additional symptoms

Other symptoms that a person with insomnia may have include the following:

• Headaches
• Irritability
• Anxiety
• Depression
• Gastrointestinal problems

Diagnosis

Doctors use a number of approaches to diagnose and measure insomnia symptoms. Patients may need to fill out questionnaires, keep diaries, have certain blood tests and even undergo an overnight sleep study. Understanding the individual symptoms a person is experiencing can help the doctor to decide on the most appropriate treatment plan.

Sleep log

This is a simple diary the patient keeps that tracks the details of their sleep such as bedtime, time of waking up and feelings of sleepiness throughout the day. This log may also help a doctor to work out any underlying cause of the insomnia.

Sleep inventory

This is a comprehensive questionnaire that is used to collect data about current health, medical history and sleeping routine.

Blood tests

Certain blood tests may be carried out to check for medical conditions that disrupt sleep and cause insomnia such as hyperthyroidism.

Overnight sleep study

Also known of as polysomnography, a sleep test involves the patient sleeping in a laboratory set up overnight in a comfortable bed so that information can be collected about their night-time sleep. An electroencephalogram is carried out to monitor the patient’s brain activity during the different stages of sleep. This non-invasive test also measure factors such as body movement, oxygen levels, heart rhythm and breathing patterns.  

Further Reading

• All Insomnia Content
• Insomnia – What is Insomnia?
• Insomnia Causes
• Insomnia Treatment
• Insomnia in Pregnancy

Written by

Sally Robertson

Sally has a Bachelor's Degree in Biomedical Sciences (B.Sc.). She is a specialist in reviewing and summarising the latest findings across all areas of medicine covered in major, high-impact, world-leading international medical journals, international press conferences and bulletins from governmental agencies and regulatory bodies. At News-Medical, Sally generates daily news features, life science articles and interview coverage.