Sudden insomnia is usually a form of acute insomnia, which means that insomnia appears quickly, then lasts for a short time.

People with insomnia typically have trouble getting to sleep, staying asleep, or even getting good quality sleep. A lack of sleep can impact a person’s ability to perform daily activities.

Sudden insomnia is one of the most common sleep problems. According to 2020 research, nearly a third of the population reports new or acute insomnia yearly. Some cases of sudden insomnia last for a long time and may lead to a more chronic condition.

No single factor explains all cases of sudden insomnia. A combination of environment, genetics, health, stress, lifestyle, and other factors may play a role.

Read on to learn more about sudden insomnia, including its causes, symptoms, and when a person should seek medical attention.

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Sudden insomnia means that symptoms of insomnia appear abruptly rather than gradually. It is often acute or short-term. Short-term insomnia can last between a few days to weeks.

Sudden insomnia is a symptom and not a diagnosis. While there are many different causes, some require medical treatment, but others — such as poor sleep habits — may respond well to lifestyle changes.

Some common signs and symptoms of sudden insomnia include:

  • difficulty falling asleep
  • frequent nighttime waking
  • difficulty falling back asleep after waking
  • extreme daytime tiredness
  • changes in sleep patterns, such as having more nightmares or not dreaming

Insomnia does not necessarily mean that a person is sick or in poor health, but it can be an early symptom of some health problems, such as sleep apnea.

The fact that insomnia is sudden does not necessarily mean anything about its cause. Sudden and chronic insomnia have similar causes.

Research typically finds that insomnia is a state of hyperarousal. This means that the brain and body are more active than they should be. Many different factors can cause this phenomenon.

People with insomnia tend to have:

  • higher levels of nighttime cortisol, a type of hormone
  • higher levels of blood sugar, or glucose
  • higher nighttime body temperatures

Some of the more common causes include:

Hormonal changes

Hormones are the body’s chemical messengers. Changes in hormone levels, either from normal life changes like pregnancy and menopause, or disorders that affect the thyroid and other hormone-secreting organs, may cause sleep issues.

For example, hyperthyroidism may cause a person to feel very awake and alert. A person may experience a racing heart of anxiety that further intensifies feelings of restlessness and insomnia.

Lifestyle factors

Numerous lifestyle factors can contribute to the development of insomnia. Insomnia may appear suddenly when a person’s lifestyle changes. It can also happen gradually, or suddenly appear even after a person has had an unhealthy lifestyle for a long time.

Some lifestyle factors include:

  • drinking too much caffeine, especially before bed
  • drinking too much alcohol
  • exercising right before bed
  • watching TV or playing with a phone in bed
  • thinking about or doing stressful things right before bed
  • an irregular sleep schedule
  • shift work that disrupts a person’s natural circadian rhythm

Sleep environment

A person’s sleep environment can make it more difficult to sleep.

Loud noises, an uncomfortable bed, a room that is too hot, or a new sleeping environment may contribute to sleep issues. Also, a sudden change in a person’s sleep environment can trigger sudden insomnia.

Sleep disorders

Numerous sleep disorders can cause insomnia, and sometimes it comes on suddenly. Some examples include:

  • sleep apnea, which may cause a person to repeatedly wake because of breathing difficulties
  • restless leg syndrome, which can cause a person to repeatedly move their legs to relieve unusual and painful sensations
  • circadian rhythm disorders, which disrupt the body’s usual sleep-wake cycle

Mental health

Anxiety from a short-term stressor such as a job loss or moving to a new home may cause sudden insomnia. Chronic mental health issues such as depression may also lead to sleep difficulties.

Physical conditions

A number of physical health conditions may contribute to insomnia by making sleep uncomfortable or painful. For example, chronic pain, migraine, or a broken bone may all lead to insomnia.

Treating the underlying physical cause may help.

Learn more about how doctors diagnose insomnia.

Pregnancy often causes insomnia and sleep difficulties.

A 2021 meta-analysis reports the overall prevalence of insomnia during pregnancy to be 38.2%, but other sources suggest the figure is much higher.

According to an older 2015 paper, around 66% to 94% of pregnant people report sleep difficulties during pregnancy.

Sudden insomnia during early pregnancy can happen for several reasons, including:

  • nausea and vomiting from morning sickness
  • a rise in progesterone, which causes symptoms such as sleep apnea and daytime sleepiness, as well as the cycle of excessive napping and more frequent nighttime waking
  • back pain
  • more frequent urination

While it is not usually a cause for concern, people should discuss all new pregnancy symptoms with a healthcare professional.

When an underlying medical condition — such as hyperthyroidism — causes sudden insomnia, treatment requires addressing this cause.

Treatments for unexplained insomnia might include:

  • Sleep hygiene: Sleep hygiene means adopting strategies that make sleep easier. This includes using the bed only for sleep or sex, not watching TV or playing with a phone in bed, sleeping in a cool and dark room, and ensuring the bed is comfortable.
  • A consistent sleep routine: Going to bed and waking at the same time each day, regardless of how much sleep a person gets can help. If a person cannot fall asleep, they should leave the bed and do something else.
  • Sleep restriction: This means minimizing or eliminating daytime naps and reducing the total time a person sleeps. This can help a person feel more tired, making it easier to fall and stay asleep.
  • Psychotherapy: Psychotherapy can ease underlying mental health issues such as depression and anxiety. Cognitive behavioral therapy for insomnia (CBT-I) and some other insomnia treatments can help a person calm racing thoughts, adopt healthier sleep practices, and manage insomnia.

While sleep medications can help with short-term insomnia, they are potentially addictive. They are not intended for long-term use, so it is important to pursue other treatment strategies while using sleeping medication.

Insomnia itself is not a progressive disease. However, it can cause many serious issues, such as:

  • daytime sleepiness that increases the risk of car accidents and injuries
  • intense fatigue that leads to depression, stress, or difficulty concentrating
  • work or relationship problems from chronic fatigue and trouble concentrating

Emerging research also suggests that insomnia may be a risk factor for other diseases.

For example, a 2019 study investigating cardiovascular disease incidence among half a million adults in China, found that insomnia was a risk factor. However, it is unclear whether insomnia or sleep deprivation causes cardiovascular disease, or if the two diseases share similar risk factors or disease pathways.

See a doctor if:

  • A person develops other symptoms along with insomnia, such as pain or trouble breathing at night.
  • A person’s insomnia progressively worsens or does not improve with home treatment.
  • A person can only sleep with the use of medication sleep aids.
  • A person has mental health issues such as anxiety or depression.

Sudden insomnia can be very frustrating. A person might lie awake at night for hours, unable to sleep, only to feel exhausted the next day. Sudden insomnia is a symptom, not a diagnosis, and it may point to a wide range of issues, from serious health problems to temporary lifestyle inconveniences.

Insomnia can also undermine relationships, well-being, work, and more.

The condition is treatable. People living with insomnia who do not get relief from self-care strategies should see a healthcare professional for additional support.