Nightmare disorder is referred to by doctors as a parasomnia — a type of sleep disorder that involves undesirable experiences that occur while you're falling asleep, during sleep or when you're waking up. Nightmares usually occur during the stage of sleep known as rapid eye movement (REM).
You normally go through four to six sleep cycles a night, cycling through the sleep stages in about 90 minutes. Your REM stage lengthens with each cycle, from several minutes in the first cycle to up to an hour in the last. You're more likely to have a nightmare in the second half to the last third of your night.
A nightmare may involve these features:
- Your dream seems vivid and real, often becoming more disturbing as the dream unfolds
- Your dream storyline is usually related to threats to your safety or survival
- Your dream wakes you
- You feel scared, anxious, angry, sad or disgusted as a result of your dream
- You feel sweaty or have a pounding heartbeat, but do not leave the bed
- You can think clearly upon awakening and can recall details of your dream
- Your dream occurs near the end of your sleep time
- Your dream keeps you from falling back to sleep easily
You may have nightmare disorder if, in addition to the above:
- The sleep disturbance causes significant distress or problems with functioning during the day
- Medications or physical or mental disorders do not adequately explain the fact that you have nightmares
Children's nightmare content varies with age, typically becoming more complex. While a young child might dream of monsters, an older child might have nightmares about school or difficulties at home.
When to see a doctor
Occasional nightmares aren't usually a cause for concern. If your child has nightmares, you can simply mention them at a routine well-child exam.
Talk to your doctor sooner if nightmares:
- Occur frequently and persist over time
- Routinely disrupt sleep
- Cause fear of going to sleep
- Cause daytime behavior problems
Nightmares are only considered a disorder if disturbing dreams cause you distress or keep you from getting enough sleep. Nightmares can be triggered by many factors, including:
- Stress. Sometimes the ordinary stresses of daily life, such as a problem at home or school, trigger nightmares. A major change, such as a move or the death of a loved one, can have the same effect.
- Trauma. Nightmares are common after an accident, injury or other traumatic event. Nightmares are prominent in post-traumatic stress disorder (PTSD).
- Sleep deprivation. Changes in your schedule that cause irregular sleeping and waking times or that interrupt or reduce the amount of sleep can increase your risk of having nightmares.
- Medications. Some drugs — including certain antidepressants, blood pressure medications, beta blockers, and drugs used to treat Parkinson's disease or to help you stop smoking — can trigger nightmares.
- Substance abuse. Alcohol and illegal drug use or withdrawal can trigger nightmares.
- Scary books and movies. Reading scary books or watching scary movies, especially before bed, can be associated with nightmares.
- Other disorders. Some medical conditions and mental health disorders as well as other sleep disorders can be associated with having nightmares. For instance, anxiety can be associated with a higher likelihood of recurrent nightmares.
Nightmare disorder may cause:
- Excessive daytime sleepiness, which can lead to difficulties at school or work, or problems with everyday tasks, such as driving and concentrating
- Problems with mood, if the anxiety from the dream continues to bother you
- Resistance to going to bed or to sleep for fear you'll have another bad dream