Insomnia: An Overview

According to a study by Ohayon (2002), anywhere from 5 to 50% of the population suffers from some form of insomnia depending on your define insomnia. Insomnia can be short-term or long-term, and people can experience specific sub-types of insomnia.

As a general definition, insomnia can be defined as difficulty falling asleep, staying asleep, and/or waking up too early. This issue is usually related to feelings of unrefreshing sleep and daytime impairment (e.g., feeling more irritable, loss of concentration, and being more tired).

In this post, I provide brief information on different operationalizations of insomnia to shed light on some of the different types of insomnia that can exist in adulthood.  

Acute Insomnia

Acute insomnia is a short-term type of insomnia that usually lasts a few days to a few weeks. Acute insomnia is typically a result of a stressor that disrupts sleep for a short period of time. For example, preparing for an exam, transitioning into a new job, or having a baby.

Usually, acute insomnia resolves itself when the stressor is no longer present. However, for some people, their sleep problems persist and may become chronic insomnia.

Chronic Insomnia

Chronic insomnia, otherwise known as insomnia disorder, is a longer-term type of insomnia that persists for at least 3 months and occurs 3 days of the week.

Chronic insomnia is a diagnosable disorder because of how persistent, pervasive, and impairing the disorder is to a person. Typically, chronic insomnia occurs because a person becomes excessively worried about their sleep and counterproductively engages in behaviours that further impact their ability to produce sleep. For example, they may spend a lot of time in bed worrying about not being able to sleep, which creates an association between the bed and wakefulness.

Here’s a post if you’re interested in learning more about the difference between acute and chronic


Beyond length of insomnia, there are specific subtypes of insomnia that people can experience.

Sleep Onset Insomnia

Sleep onset insomnia refers to when a person has difficulty with falling asleep. Good sleepers usually take between 10-30 minutes to fall asleep on average.

In our clinical work, we usually use a 30-minute threshold for what is considered elevated sleep onset. This means that if a person takes on average more than 30 minutes to fall asleep, then this could be considered a problem with sleep onset.

Interestingly, acute pain (e.g., a sore tooth, a bruise) can lead to problems with sleep onset.

Sleep maintenance insomnia

Sleep maintenance insomnia is when a person has difficulties with sleeping soundly throughout the night. Although awakenings in the night are very common, people with sleep maintenance issues will spend more time in the middle of the night awake. They may take hours to fall back asleep in some cases.

As an interesting fact, the use of alcohol or cannabis at night can lead to quicker sleep onset but more frequent awakenings, as the chemicals in the body are being broken down which can lead to higher arousal levels.

Terminal Insomnia

Terminal insomnia refers to waking up earlier than planned. For example, a person may typically sleep at 11pm and wake up at 7am. If they were to start waking up earlier than their body usually plans to frequently (e.g., 4 or 5am), then they may be experiencing terminal insomnia symptoms.

On the other hand, if a person who is a morning bird consistently sleeps at 9:00pm and wakes up around 4 or 5am, then that would not be considered terminal insomnia. That’s just their natural circadian rhythm at work.

Comorbid Insomnia

Comorbid insomnia is simply a fancy term when insomnia exists with another disorder (e.g., chronic pain, depression, anxiety, cardiovascular diseases).

Not many years ago, insomnia was seen as generally secondary to other disorders. For example, people would consider depression to be ‘primary’ and insomnia as a ‘secondary’ effect of depression.

We now know that these relationships are bidirectional and insomnia can exist before depression and stick around even if depression is treated (e.g., Stepanski & Rybarczyk, 2006). Moreover, treating insomnia can also improve the other condition, such as in chronic pain and depression.

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Best wishes,