Snooze University

What Causes Sudden Insomnia? (Acute Insomnia)

by Dale Cudmore | Updated: Jan 27, 2023

There are different types of insomnia, and depending on who you ask, sudden insomnia might be called either acute, transient, or adjustment insomnia.

These conditions describe sudden sleep issues that typically (but not always) last for a short term.

Most sleep research focuses on chronic insomnia, but more research lately has focused on sudden insomnia. I’ve summarized that research in this post.

What Is Sudden Insomnia

To start with, what’s the difference between chronic insomnia and sudden insomnia?

The only real difference is time frame.

To be diagnosed with insomnia disorder (i.e. chronic), sleep issues must be present for at least 3 months (1):

Sleep difficulties occur at least 3 nights per week for at least 3 months, and are not better explained by use of substances, medications, or by another disorder

If someone has historically been a good sleeper, but is suddenly having issues, they will likely be diagnosed with acute insomnia.

SummaryIn many cases, sudden insomnia will go away on its own, but it does often progress to chronic insomnia.

Sudden Insomnia Is Very Common

One study found that in a sample of good sleepers, 27% of them experienced acute insomnia over the course of a year (2).

Of those people that had sleep issues:

  • 1.8% went on to develop chronic insomnia
  • 72.4% recovered back to good sleep
  • 19.3% had intermittently poor sleep (but not chronic insomnia)

And a few percent dropped out of the study, but we still get a good picture of the results.

SummaryAbout three quarters of people with sudden insomnia will get back to good sleep without treatment. However, the rest will continue to have some degree of sleep issues if not treated.

Causes of Sudden Insomnia

The fact that acute insomnia arises all of a sudden indicates that there must be a trigger.

While there are some obvious causes like binge eating or drinking (or certain foods like sugar cause insomnia in some people), the trigger is typically stress-related.

In plain terms, your brain and body is willing to defer sleep because it feels like there’s something more important to do or process (3).

Common causes of acute insomnia include (4):

  • Losing someone close to you
  • Job changes
  • Traveling
  • Change-related stress (e.g. pregnancy insomnia)
  • Financial worries
  • Health concerns
  • Having more things than usual that you feel you “need to do”
  • Stress from exams, tests, or presentations
  • Not being happy with your life situation overall
  • Interpersonal conflicts

Note that sudden insomnia isn’t always caused by an obvious trigger. It can also be an accumulation of small stressors.

Currently, models suggest that everyone has their own “insomnia threshold,” related to the amount of stress in their life.

If you surpass this threshold, there are consequences like sleep trouble.

It’s possible to surpass this threshold from a single stressful event (like from the list above), or from an accumulation of daily annoyances.

Some people are always close to this threshold, and tip over it over on a regular basis when small stressors arise. These are the people most likely to develop intermittent sleep issues, and even chronic insomnia.

SummarySudden insomnia is triggered by stressful events. It can be caused by a single large stressor, or many small ones that build up.

How Is Acute Insomnia Treated?

Each case of acute insomnia will be approached differently by a doctor.

For some triggers, the cure is just time. For example, stress from grieving over a lost one takes time to resolve, and may require therapy.

The standard treatment is currently a pharmacological approach (i.e. sleep medication), alongside cognitive behavioral therapy (CBT) (4).

While research is still a bit mixed, there are studies that show just a single hour long session of CBT can increase the odds of fixing acute sleep issues by up to 4x in a 1 month period (5, 6).

...60% of those in the CBT-I group had remitted by 1 mo compared to 15% of those in the control group.

CBT essentially helps you learn to identify thoughts that lead to stress, and reframe them in a more healthy way.

SummaryDepending on the situation, physicians typically prescribe either sleep medication, CBT, or both to treat sudden insomnia.

Can Sudden Insomnia Turn Into Chronic Insomnia?

The last question we haven’t addressed is how exactly temporary sleep trouble turns into chronic sleep trouble.

What most people don’t understand is that insomnia can quickly turn into a vicious cycle.

Poor sleep results in (7):

  • More stress
  • Sleep anxiety
  • Poorer eating decisions
  • Less exercise
  • Depressive symptoms
  • Daytime sleepiness

All of these can either directly or indirectly make your sleep hygiene worse.

In turn, that can make sleep issues even worse, which creates a negative feedback look that can be hard to get out of.

A lot of these vary in individuals, but in some, even short term insomnia symptoms can turn into long term sleep issues.

SummaryIf you do have any sleep trouble that doesn’t quickly resolve itself, you should see a doctor for diagnosis and treatment.


  1. Clinical Management of Insomnia Disorder
  2. The Natural History of Insomnia: the incidence of acute insomnia and subsequent progression to chronic insomnia or recovery in good sleeper subjects
  3. The Varied Nature of Insomnia
  4. Acute insomnia: Current conceptualizations and future directions
  5. Cognitive Behavioral Therapy for Insomnia and Acute Insomnia
  6. Treating Acute Insomnia: A Randomized Controlled Trial of a “Single-Shot” of Cognitive Behavioral Therapy for Insomnia
  7. The Natural History of Insomnia: Acute Insomnia and First-onset Depression

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.