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The 6 Different Types of Insomnia According to the WHO

by Dale Cudmore | Updated: Jan 20, 2023

The answer to how many different types of insomnia there are depends on who you ask.

There are 2 main medical classification lists used around the world.

The International Statistical Classification of Diseases and Related Health Problems (ICD) standard is used by doctors around the world and is the most popular. It’s created and maintained by the World Health Organization (WHO) and is available for free and is updated every few years and has 6 main different types of insomnia.

The Diagnostic and Statistical Manual of Mental Disorders (DSM) is used mainly in America, and has 3 mental disorders involving insomnia.

I’ll summarize both here.

The 6 Main Types of Insomnia

Primary Insomnia

Other names: Idiopathic insomnia, Chronic insomnia

ICD code: F51.01

Primary insomnia describes difficulty getting to sleep or maintaining sleep over a long period of time. However, it does not apply to people with mental disorders, substance use issues, or other medical conditions. Those fall under different types of insomnia.

There’s a wide variety of potential causes of primary insomnia. If the cause isn’t evident to your doctor based on your history, he or she can recommend a sleep study.

Depending on the particular issue (e.g. early morning awakening insomnia versus trouble getting to sleep), the solution may involve medication, counseling, or simple lifestyle changes. See what doctors prescribe for insomnia for more details.

Adjustment Insomnia

Other names: Transient insomnia, Acute insomnia

ICD code: F51.02

Adjustment insomnia describes a short period where someone has trouble sleeping. This is typically caused by a specific event (mourning the loss of someone) or by a temporarily stressful situation (changes in your job or traveling).

This is typically what pregnancy insomnia would be categorized as.

This is one of the few situations where insomnia will typically resolve on its own over time.

If you'd like to read more, see our page on what causes sudden insomnia.

Paradoxical Insomnia

ICD code: F51.03

Paradoxical Insomnia is a rare condition where patients appear to be asleep to those around them, but feel fully awake for most of the night.

They are very aware of their surroundings during this period, and may believe that they only slept a few hours, when in fact they slept many more. However, the sleep quality is usually low, so people with paradoxical insomnia still usually feel unrested even on “good” days.

Psychophysiologic Insomnia

ICD code: F51.04

This is the type that most of us think about when you think about insomnia. It is the most common subtype of insomnia.

It describes insomnia that is caused by biological (physical) or psychological (mental) problems. Things like overthinking and anxiety typically fall into this category.

Insomnia Due to Other Mental Disorder

Other names: Anxiety disorder, Depression

ICD code: F51.05

Having some anxiety at night doesn’t necessarily mean that you have a full blown anxiety disorder.

However, people that struggle with anxiety disorder or depression often develop insomnia. This type of insomnia was created for them, as they will likely need specialized treatment to treat the underlying cause.

Other Insomnia Not Due to a Substance or Known Physiological Condition

Other names: Mood insomnia

ICD code: F51.09

This is not a common diagnosis, but is sometimes used when a patient doesn’t fall into any of the above categories. It’s usually related to adjustment insomnia that hasn’t fully resolved over a longer time period.

Insomnia Disorders According to the DSM

Insomnia can make it hard to stay awake during the day

Just for an alternative perspective, we can look at how the DSM categorizes insomnia.

It’s much more general than the categories set by the ICD.

1. Insomnia Disorder

Insomnia Disorder (formerly known as primary insomnia) is the main type of clinical insomnia.

There are many conditions that must be met to be diagnosed with insomnia disorder:

  1. One of: Difficulty getting to sleep, maintaining sleep, or waking up.
  2. Difficulty getting to sleep lasts at least 3 months, and occurs at least 3 nights per week.
  3. You have difficulty sleeping despite ample opportunity for sleep.
  4. Your sleeping troubles cannot be explained by another disorder like sleep apnea.
  5. It’s not a result of substance use (medication or abuse of a drug).
  6. The sleep issues cause significant distress or impairment in other areas of your life.

That’s quite a few criteria.

What happens if you only have a few of them? Well, then you probably fall under one of the other 2 types of disorders involving insomnia.

2. Other Specified Insomnia Disorder

When a patient doesn’t meet all of the conditions for Insomnia Disorder, a physician can still diagnose them with Other Specified Insomnia Disorder.

For example, perhaps someone meets all the criteria, but it hasn’t quite been 3 months yet.

3. Unspecified Insomnia Disorder

As the name implies here, this type is even more vague than the previous 2 types of insomnia.

Unspecified Insomnia Disorder refers to people who have symptoms of Insomnia Disorder that significantly impact their lives, but do not meet the full conditions of either of the above conditions.

It can also be assigned by clinicians when there are simply insufficient (or unclear) reasons for a patient’s sleep troubles.

Common Questions About the Different Types of Insomnia

How many people have insomnia?

Recent studies show that about 6-10 percent of people have clinically defined Insomnia Disorder.However, estimates show that up to 70% of adults have some level of difficulty sleeping.

What is the most common type of insomnia?

The most common type of insomnia in a general sense is onset insomnia, which describes difficulty getting to sleep (as opposed to staying asleep or waking up).

What are the main causes of insomnia?

There are many possible causes of insomnia. The most common ones are anxiety, pregnancy, and other disorders like depression or restless leg syndrome.

How do you treat insomnia?

There are many possible treatment options. The most promising ones are medication, sleep hygiene education, cognitive behavioral therapy (CBT), and sleep restriction therapy.

Is it possible to die from insomnia?

Realistically, you can’t die from insomnia. However, there is one condition called Fatal Familial Insomnia (FFI), which is extremely rare, where someone can die from other symptoms.

Medical Disclaimer: The information on is not intended to be a substitute for physician or other qualified care. We simply aim to inform people struggling with sleep issues about the nature of their condition and/or prescribed treatment.

About the authorDale is the founder of Snooze University and a sleep researcher. I overcame my sleep issues and now I'd like to help you do the same by summarizing the latest sleep studies for you.