Definition, Symptoms And Causes Of Insomnia

insomnia o'clockInsomnia is by far the most common sleep problem. In any annual survey over 35% of Americans will report they had it in the last 12 months.

People regularly declare themselves as ‘insomniacs’ without ever asking for a doctor’s opinion.

The reality is though that many people will experience insomnia in one form or another at some point in their lives.

Insomnia can actually be quite confusing to understand – it is more complicated that simply not being able to sleep.

There are many different types, patterns, symptoms and causes. We will go through each of these in turn in this article, so hopefully you will have a clearer picture of this frustrating sleep problem.


1. The definition of insomnia

the definition of insomnia is not getting enough sleepThere is no standard insomnia definition – it varies amongst medical sources and countries. Despite the differences in wording, many definitions look a little bit like this:

Insomnia can be defined as a difficulty getting to sleep, or staying asleep. This results in a lack of quality restorative sleep. The individual then does not feel refreshed, has problems in daily functioning, and often feels distressed.

This is a long definition, so a simpler version would be:

The definition of insomnia is not being able to get good enough sleep.

It is not quite as simple as this though as there are different types of insomnia. And so the diagnosis of these different types means a slightly different definition.

We’ll take a look at the various different ways insomnia is broken down in to sub-sections now.


2. Insomnia sub-sections


The 2 main types of insomnia:

The first split is based on whether insomnia exists on its own, or is caused by something else. The following two terms are then applied depending on which case it is:

Primary insomnia

Primary insomnia means a person is having problems sleeping, but it is not being caused by something else. The problem therefore exists all on its own.

Secondary insomnia

Secondary insomnia is when a person is experiencing sleeplessness as a result of other issues. For example a physical or mental health condition, medication they are taking, or pain. This is much more common than primary insomnia. It is often seen as a ‘symptom’ rather than a sleep disorder in this case.


The 3 main categories of insomnia:

To make matters even more confusing, there are also 3 categories of insomnia. These relate to how often a person experiences sleep problems:

Chronic insomnia

Chronic insomnia applies to those unlucky few who suffer from sleeping problems for longer than a month. This is the kind of insomnia that can be long-term and lead to many problems in daily functioning.

Acute insomnia

Acute insomnia is when a person has difficulty sleeping for less than a month, but more than a few days. Again it often leads to problems in daily functioning. It may be that someone suffers acute insomnia phases over time, with periods of normal sleep in between.

Transient insomnia

When a person has a few nights of poor sleep that lasts less than a week it is called transient insomnia. Often this can be caused by factors such as changes in the environment, stress or lifestyle choices.


insomnia infographic


Patterns relating to time:

Finally there are different patterns of insomnia, depending on exactly which form the sleep problems take each night. The patterns are usually split into these sub-sections:

Onset insomnia

Onset insomnia is very common, and refers to when a person cannot get to sleep to begin with. It should not be confused with delayed sleep phase syndrome DPS) though.  DPS is something teenagers often experience naturally when they end up going to bed later and waking up later.

Sleep maintenance insomnia

Sometimes known as ‘middle of the night insomnia’ this is when a person wakes up in the middle of the night, and cannot fall asleep again. However, there are arguments that it may not really be a problem to wake up for an hour or two in the middle of the night.

Terminal insomnia

When someone wakes up earlier than they want to, and cannot get back to sleep again, it is called terminal insomnia. This is often experienced by older people, especially if they go to bed earlier.

It is also often related to depression, but can equally be caused by the environment. For example having too much daylight coming into the bedroom at sunrise.

Sleep state misperception

sometimes we think we slept worse than we really didSleep state misperception is also important to mention. This is not really a form of insomnia, but when a person feels they slept far worse than they did.

Sometimes it can feel that it took much longer to fall asleep than it really did. Or if someone wakes up a few times in the night they may feel they were awake for a long time.

So in the morning a person may feel that they didn’t sleep well, but in actual fact they got much more sleep than they fear.


3. What causes insomnia?

There is a huge range of possible causes of insomnia. For this reason it is advisable to ask a medical professional to identify the cause and recommend the right treatment.

To find out what people believe causes their insomnia, we ran a poll asking people to tell us what they thought. 1029 people responded, and the results can be seen in the table below:


CausePercentage of people
Over-active mind58%
Worry, stress or anxiety24%
Feeling uncomfortable11%
My partner1%
Medical condition1%


The results of our poll suggest that people believe it is generally their own mind that keeps them awake.

Some of the people voting in the poll though may not have been aware of the real reason keeping them awake at night.

That is why it is important to talk to a doctor if you have serious sleep problems. If you try to diagnose yourself, you may miss something which could easily be treated.

Now let’s have a closer look at some of the main causes of insomnia:


Anxiety, stress and worry

In the fast pace of modern life, there are countless things to worry about. And these worries often surface at night when the lights go out. Here are just a few examples of the kinds of thoughts that can cause insomnia:

  • Worrying about relationships or family
  • Thinking about work
  • Stress about finances
  • Being excited about something coming up in the future.
  • Dwelling on the past
  • Just having random thoughts
  • Having lots of the above thoughts at once!

If stress or worry is keeping you up at night then there are things you can do about it. A good starting point is to try our recommended relaxation techniques for sleep.


An underlying health condition

Sometimes insomnia can be a symptom of an underlying health condition. Or sometimes insomnia can exist alongside another health condition (this is called co-morbid).

Some possible health conditions that can cause, or be co-morbid with insomnia are:


Physical health conditions:

  • Chronic, long-term pain
  • Recovering from medical treatment or surgery
  • Cancer and cancer treatment
  • Other sleep disorders such as apnea, narcolepsy, sleep terrors or sleep paralysis
  • Heart burn
  • Heart disease
  • Respiratory problems – asthma for example
  • Neurological diseases such as Parkinson’s or Alzheimer’s
  • Hyperthyroidism (over-active thyroid)
  • Arthritis
  • Incontinence
  • Prostrate problemstreating a health condition can help improve insomnia

Some women may also find that hormonal changes during menstruation or menopause can lead to insomnia. If you are unsure if a health condition could be causing insomnia, talk to a doctor to rule it out.


Mental health conditions:

  • Depression
  • Anxiety
  • Chronic stress
  • Bipolar disorder
  • Post Traumatic Stress Disorder (PTSD)
  • Schizophrenia
  • Obsessive compulsive disorder

Again, if you do have a mental health condition, then you can talk to your doctor about insomnia. It may even be that medication you are prescribed is causing it.


Circadian Rhythm Disorders and Disruptions

The Circadian rhythm is the daily pattern of waking and sleeping that should repeat more or less the same way every day. It is partly controlled by our internal body clock, which is unfortunately quite sensitive.

When our body clock, and rhythm, is disrupted it can lead to insomnia. Possible reasons for the disruption, and types of Circadian rhythm sleep disorders include:

  • Jet-lag
  • Shift work
  • Seasonal Affective Disorder (SAD)
  • Delayed Sleep Phase Disorder (DPSD)


Issues with sleep hygiene:

Sleep hygiene is about the choices you can make in your every day life that affect your sleep. There is a surprising variety of choices you make which can negatively affect your quality of sleep.

Although chronic insomnia is not usually impacted so much by sleep hygiene, acute and transient often is. So you should have a think about your lifestyle choices if you only occasionally have trouble sleeping. Here are a few example:

  • Not following a strict pattern of waking and sleeping
  • Watching TV or using a computer in bed
  • Eating too big a meal before bed
  • Drinking caffeine or alcohol too late in the day
  • Not getting enough fresh air or exercise

We have an extensive section about all these factors and many more, including some unusual but effective ideas. We highly recommend you read carefully through our section on sleep hygiene.


Medication and other substances:

Some medications and substances can lead to insomnia, such as:

  • Antidepressants
  • Cold and Flu medications, especially those containing alcohol
  • Pain relievers that have caffeine in them
  • Diuretics
  • Corticsteroids
  • Thyroid hormone
  • High blood pressure medications
  • Certain antibiotic drugs, e.g fluoroquinolone
  • Alcohol (despite thinking it can help you sleep, it actually disrupts sleep quality)
  • Caffeine

Many illegal drugs, particularly stimulants and hallucinogenics, can also lead to difficulties sleeping. This can be due to the direct effects the drugs have on people. The ‘come down’ from the drug can also lead to low mood and irritability, or withdrawal symptoms.

When people stay up all night taking drugs it can lead to several days of poor sleep quality. This can be due to the change in the circadian rhythm, sleep deprivation, and the subsequent low moods.


4. Symptoms of insomnia

quote about the symptoms

Different people may experience different symptoms of insomnia. This is because there are so many types of insomnia as we have seen already.

And it is in many ways a subjective problem. One person may sleep 6 hours and feel fine; but another person may sleep 6 hours and feel terrible the next day.

Moreover, insomnia is often linked with another medical condition. And so the symptoms can also be linked with symptoms of the other condition.

Some examples of possible symptoms include:

  • Having difficulty falling asleep
  • Waking up in the middle of the night and not being able to fall asleep again easily
  • Waking up several times throughout the night
  • Waking up early in the morning and not going back to sleep
  • Feeling unrefreshed the next day – not having enough restorative sleep
  • Having problems during the day with concentration, memory and mental sharpness
  • Poor motor skills – being uncoordinated
  • Feeling sleepy, irritable and impatient during the day
  • Poor social interaction due to mood
  • Unable to wake up without an alarm, or depending on the snooze button
  • Needing medication or other substances to fall asleep
  • Needing substances to keep awake


5. Treatment of insomnia

By now you will have got the picture we hope that there is no one-size-fits-all approach to insomnia. We recommend your first step be to visit a medical practitioner for advice.

One of the good things with the complicated nature of insomnia is how it can be cured by addressing the underlying problem.

So for example if it is a medication keeping you awake, then changing medication should clear up the insomnia.

Or if it is a physical health issue, then diagnosing and treating that condition may help you sleep better.

We also recommend, as do most medical professionals, that you look into sleep hygiene. Whichever form of insomnia you have it can only do you good to follow good sleep hygiene principles.

This may resolve the insomnia completely – and even if it doesn’t, it should help at least a little.

And of course there are sleeping pills. This is usually down to a doctor to prescribe, even though you can buy some over the counter. If you do go down this route, we still recommend you look into the self-help options available.

And finally in terms of self-help, there are many products designed to help people sleep. You can have a look at some of our sleep aid reviews for some ideas of what may help you sleep better.



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