Insomnia is a common sleep disorder that makes it hard for you to fall asleep or stay asleep. It leads to daytime sleepiness and not feeling rested or refreshed when you wake up.

According to the Cleveland Clinic, approximately 50 percent of adults experience occasional insomnia. One in 10 people report having chronic insomnia.

Insomnia can affect anyone, but it’s considerably more common in women and older adults. It can last a few days, weeks, or continue long term. Stress, menopause, and certain medical and mental health conditions are common causes of insomnia.

There are a few different types of insomnia. Each type is characterized by how long it lasts, how it affects your sleep, and the underlying cause.

Acute insomnia

Acute insomnia is short-term insomnia that can last from a few days to a few weeks. It’s the most common type of insomnia.

Acute insomnia is also referred to as adjustment insomnia because it typically occurs when you experience a stressful event, such as the death of a loved one or starting a new job.

Along with stress, acute insomnia can also be caused by:

  • environmental factors that disrupt your sleep, such as noise or light
  • sleeping in an unfamiliar bed or surroundings, such as a hotel or new home
  • physical discomfort, such as pain or being unable to assume a comfortable position
  • certain medications
  • illness
  • jet lag

Chronic insomnia

Insomnia is considered chronic if you have trouble sleeping at least three days per week for at least one month.

Chronic insomnia can be primary or secondary. Primary chronic insomnia, which is also called idiopathic insomnia, doesn’t have an obvious cause or underlying medical condition.

Secondary insomnia, also called comorbid insomnia, is more common. It’s chronic insomnia that occurs with another condition.

Common causes of chronic insomnia include:

Onset insomnia

Onset insomnia is trouble initiating sleep. This type of insomnia can be short term or chronic.

Any of the causes of acute and chronic insomnia can make it difficult to fall asleep. Psychological or psychiatric issues are the most common causes. These include stress, anxiety, or depression.

According to a 2009 study, people with chronic onset insomnia often have another sleep disorder, such as restless leg syndrome or periodic limb movement disorder.

Caffeine and other stimulants can also prevent you from falling asleep.

Maintenance insomnia

Maintenance insomnia is difficulty staying asleep or waking up too early and having trouble getting back to sleep. This type of insomnia causes you to worry about not being able to fall back asleep and not getting enough sleep. This interferes with sleep further, creating a vicious cycle.

Maintenance insomnia can be caused by mental health conditions, such as depression. Other medical conditions that can cause you to wake up include:

Behavioral insomnia of childhood

Behavioral insomnia of childhood (BIC) affects approximately of children. It’s divided into three subtypes:

  • BIC sleep-onset. This type results from negative associations with sleep, such as learning to go to sleep by being rocked or nursed. They may also include having a parent present or watching TV while falling asleep.
  • BIC limit-setting. This type of BIC involves a child’s refusal to go to bed and repeated attempts to put off going to sleep. Examples of this behavior are asking for a drink, to go to the bathroom, or for a parent to read them another story.
  • BIC combined type. This form is a combination of the other two subtypes of BIC. This occurs when a child has a negative association with sleep and resists going to bed because of a lack of limit-setting by a parent or caretaker.

BIC can usually be resolved with a few behavioral changes, such as creating a healthy sleep routine or learning self-soothing or relaxation techniques.

Insomnia can cause a number of risks and side effects that affect your mental and physical health and impact your ability to function.

Risks and side effects of insomnia include:

  • decreased performance at work or school
  • increased risk of accidents
  • increased risk of depression and other mental health conditions
  • increased risk of chronic medical conditions, such as heart disease, stroke, and obesity

Treatment for insomnia varies and depends on the cause.

You may be able to treat acute insomnia at home with an over-the-counter sleep aid or by managing your stress.

Treatment for chronic insomnia may require addressing any underlying condition that’s causing your insomnia. A doctor may recommend cognitive behavioral therapy for insomnia (CBT-I), which has proven to be more effective than medication.

Diagnosing insomnia may include a physical examination and a review of your medical history to check for signs of an underlying condition.

You may also be asked to track your sleep patterns and symptoms in a sleep diary. A doctor may refer you for a sleep study to check for other sleep disorders.

See a doctor if insomnia is making it hard for you to function during the day or if it lasts more than a couple weeks. A doctor can help determine the cause of your insomnia and the most effective way to treat it.

Each of the different types of insomnia can interfere with your ability to function during the day. Acute insomnia can usually be treated at home. Left untreated, chronic insomnia can increase your risk of depression and other serious conditions.