While they're more common when you're a child, nightmares know no age. Everyone is prone to waking up, panicked, in the middle of the night, anxious and distressed from an alarming dream.
In fact, researchers say practically three-quarters of our dreams are actually nightmares. Five to 10 percent of people experience frequent nightmares, which can turn into a debilitating sleep disorder if they affect your day-to-day life.
When do the bad dreams start?
Nightmares occur only during rapid eye movement (REM) sleep, the dreaming phase, which begins after the first 70 to 90 minutes of sleep. While some of the specifics are still vague, most scientists agree that adults' bad dreams usually occur from emotional and psychological stress.
Other causes include death of a loved one, drug side effects or illness with a fever. Eating close to bedtime, which revs up the body's metabolism, may also be an instigator.
Do nightmares serve any purpose?
We're meant to learn from them, or so says evolutionary psychologist Antii Revonsuo.
"The form and content of dreams is not random but organized and selective: during dreaming, the brain constructs a complex model of the world in which certain types of elements, when compared to waking life, are underrepresented whereas others are over represented," he says in a Centre for Cognitive Neuroscience study. Revonsou based his theory around our ancestors.
Much like the simulation serum in Divergent, Revonsuo thinks dreams — and thus nightmares — evolved to simulate threatening events so we can learn to cope in the real world. Deirdre Barrett, a psychologist at Harvard University, agrees. She theorizes that nightmares are the brain's way of focusing a person's attention on issues they need to address.
Yet another theory suggests the brain's cortex is to blame. Trying to make sense of the random signals during REM sleep, the cortex builds a story.
So what causes nightmares?
Besides the stress of daily life, major events, trauma and post-traumatic stress, even moving into a new environment — nearly anything can be a trigger. In a study done by the Official Journal of the American Academy of Pediatrics, being bullied often preceded a child's nightmares.
Having more than the occasional nightmare, though, does not mean you have some sort of underlying psychosis. Rather, it showcases how you see the world — in shades of gray rather than black and white.
Can you have nightmares during a nap?
Not if your nap is 30 minutes or so, since dreams of any sort don't happen until you're at least an hour or so into your sleep.
Are my medications giving me nightmares?
It depends on what you're taking. You'll need to read the medication insert, but antidepressants, beta blockers and barbiturates have been known to cause nightmares.