A nightmare is a frightening dream that wakes you up and leaves you feeling scared, anxious or upset. Nightmares are common in children but can happen at any age. Occasional nightmares usually are nothing to worry about.

Nightmares may begin in children between 3 and 6 years old. They tend to become less common with age. Some people have them as adults or throughout their lives.

Although nightmares are common, nightmare disorder is rare. Nightmare disorder is when nightmares happen often, cause distress, disrupt sleep, make it hard to function during the day and create fear of going to sleep.

Nightmares tend to happen in the second half of the sleep period. This is because they generally occur during rapid eye movement (REM) sleep, a stage of sleep that occurs more often during the second half of the sleep period. Nightmares may occur rarely or often, even several times a night. The nightmares are generally brief, but they cause you to wake up. And it can be hard to go back to sleep.

A nightmare may include these features:

• Your dream seems vivid and real. It can be very upsetting, often becoming more disturbing as the dream goes along.
• Your dream usually includes fear or danger, but it can have other upsetting themes.
• Your dream wakes you up. You wake up alert and can remember the dream.
• You feel upset, scared, angry, sad or disgusted because of your dream.
• You may sweat or have a pounding heartbeat.
• Your dream keeps you from falling back to sleep easily.

Nightmares are considered nightmare disorder only if they:

• Happen often and keep coming back.
• Cause severe distress about going to sleep for fear of having another nightmare.
• Result in ongoing anxiety or fear, problems with paying attention or memory, daytime sleepiness, or low energy.
• Make it hard to function at work, school or in social situations.
• Cause behavior problems related to bedtime or fear of the dark.

When to see a doctor

Occasional nightmares are usually not a cause for concern. If you or your child has nightmares, you can talk about it with your healthcare professional at a routine health exam. Make an appointment to talk with your healthcare professional if nightmares:

• Happen often and continue over time.
• Routinely disrupt sleep.
• Cause fear of going to sleep.
• Make it hard to do daily activities.
• Lead to behavior problems.

If nightmares are linked to trauma or post-traumatic stress disorder (PTSD) symptoms, ask about mental health support.

Nightmare disorder is a type of parasomnia. A parasomnia is a behavior or event during sleep that is not wanted and disrupts sleep. The exact cause of nightmares is not known.

Nightmares can be triggered by many factors, including:

• Stress or anxiety. Sometimes the ordinary stresses of daily life, such as problems at home or school, trigger nightmares. A major change, such as a move or the death of a family member, can have the same effect. Having anxiety is linked with a greater risk of nightmares.
• Trauma. Nightmares are common after an accident, injury, physical or sexual abuse, or other traumatic event. Nightmares are common in people who have PTSD.
• Sleep deprivation. Changes in your sleep schedule or changes that lessen the amount of sleep you get can raise the risk of having nightmares. Insomnia is linked with a higher risk of nightmares.
• Medicines. Some medicines can trigger nightmares. Examples include some antidepressants, blood pressure medicines and beta blockers, and medicines used to treat Parkinson's disease or to help stop smoking.
• Substance misuse. Drug or heavy alcohol use or withdrawal can trigger nightmares.
• Other conditions. Depression and other mental health conditions may be linked to nightmares. Nightmares can happen along with some medical conditions, such as heart disease or cancer. Having other sleep disorders that keep you from getting enough sleep can be linked with having nightmares.
• Scary books, movies and media. For some people, reading scary books, watching frightening movies or seeing upsetting news, especially before bed, can be linked to nightmares.

Nightmares are more common when family members have a history of nightmares or other sleep disorders. Having PTSD or other mental health conditions, such as depression, can be risk factors too.

Nightmare disorder may cause:

• Severe daytime sleepiness that can cause problems at school or work or with everyday tasks, such as driving and paying attention.
• Issues with mood, such as depression or anxiety, from dreams that continue to be bothersome during the day.
• Not wanting to go to bed or to sleep for fear of having another bad dream.
• Suicidal thoughts or behavior.

Having a nightmare disorder also can disrupt the sleep of parents, a partner or other people in the house.

There are no tests routinely done to diagnose nightmare disorder. Nightmares are considered a disorder only if disturbing dreams cause you distress or keep you from getting enough sleep.

To diagnose nightmare disorder, your healthcare professional:

• Talks with you about your symptoms. Nightmare disorder is diagnosed based on your symptoms and how much nightmares affect your sleep and daily life. Your healthcare professional also may ask other people in your household about your sleep behaviors. Information about your symptoms may help to tell if you also have other sleep disorders.
• Does a physical exam. This can help to find any health conditions that may be causing the nightmares. Your healthcare professional may ask if members of your family have a history of sleep disorders. If you have anxiety, your healthcare professional may suggest you talk with a mental health professional.
• May do an overnight sleep study. Also called a polysomnography, this nighttime sleep study doesn't diagnose nightmare disorder but can help find if the nightmares are linked to another sleep disorder. In the test, sensors are placed on your body. During sleep, the sensors record and monitor brain waves, oxygen level in your blood, heart rate, breathing, and eye and leg movements. A videotape may record behavior during sleep cycles.

Treatment for occasional nightmares isn't usually needed. But if nightmares cause distress, disrupt sleep and interfere with daily functioning, treatment can help.

The cause of the nightmare disorder helps determine treatment. Treatment options may include:

• Medical treatment. If the nightmares are related to an underlying medical condition, treatment for that condition may help lessen nightmares.
• Stress or anxiety treatment. If a mental health condition, such as stress or anxiety, is linked to the nightmares, stress-lowering techniques and counseling or therapy with a mental health professional can help.
• Imagery rehearsal therapy (IRT). This involves changing the ending to a remembered nightmare when awake so that it's no longer threatening. You can write down the new ending or review it in your mind. This approach can lessen how often nightmares happen and how much distress they cause. IRT can be especially helpful for people who have nightmares as a result of PTSD.
• Medicine. Medicine is rarely used to treat nightmares. Medicine can sometimes be used for severe nightmares linked with PTSD.

If nightmares cause distress for you or your child, try these tips:

• Create a regular, relaxing routine before bedtime. A regular sleep and wake schedule and bedtime routine can help. Do quiet, calming activities, such as reading books or soaking in a warm bath before bed. Meditation, deep breathing or relaxation exercises may help, too. Also, make the bedroom comfortable and quiet for sleep.
• Offer reassurances. If your child is struggling with nightmares, be patient, calm and reassuring. After your child awakens from a nightmare, respond quickly and soothe your child at the bedside.
• Talk about the dream. Describe the nightmare. What happened? Who was in the dream? What made it scary? Remember that nightmares aren't real and can't hurt you.
• Rewrite the ending. Imagine a happy ending to the nightmare. Draw a picture of the nightmare, "talk" to the characters in the nightmare or write about the nightmare in a journal.
• Put stress in its place. If stress or anxiety is an issue, talk about it. Practice some simple stress-relief activities, such as meditation, deep breathing or relaxation. Contact a mental health professional if needed.
• Give comfort measures. Your child might feel more secure sleeping with a favorite stuffed animal, blanket or other comfort object. Leave doors open at night to offer a feeling of being connected to others. You also can better hear if your child calls out for comfort. A night light in the room may be reassuring when waking up in the night.

Talk to your healthcare professional if nightmares disrupt sleep or if you're concerned about an underlying health condition. Your healthcare professional may refer you to a sleep specialist or a mental health professional.

Keep a sleep diary for two weeks before your appointment. This can help your healthcare professional understand more about your sleep schedule, issues affecting your sleep and when nightmares occur. In the morning, record as much as you recall about bedtime rituals, quality of sleep and dreams. At the end of the day, record behaviors that may affect sleep, such as sleep schedule changes, alcohol use and any medicines taken.

Along with the sleep diary, you may want to bring a person from your household along to the appointment. That person may be able to give more information about your sleep habits.

What you can do

Before your appointment, make a list of:

• Any symptoms you have, including any that may not seem related to the reason for the appointment.
• Key personal information, including any major stresses or recent life changes.
• All medicines, vitamins, herbs or other supplements being taken, and the doses.
• Questions to ask the healthcare professional to help make the most of your time together.

Questions to ask may include:

• What is likely causing these symptoms?
• What are other possible causes?
• What kinds of tests are needed?
• Is the condition likely short term or ongoing?
• What treatment do you suggest?
• What are other treatment options?
• Are there things I can try to help with better sleep?
• Do you recommend seeing a specialist?
• Are there any brochures or other printed material that I can have? What websites do you recommend?

Feel free to ask other questions during your appointment.

What to expect from your doctor

Your healthcare professional may ask:

• When did symptoms begin?
• How often do nightmares occur, and what are they about?
• What is the usual bedtime routine?
• Is there a history of sleep problems?
• Does anyone else in your family have sleep nightmares or a sleep disorder?

Be ready to answer questions so that you have time to talk about what's most important to you.