Do personality characteristics relate to nightmares? If so, which?
Recently on The Science of Personality, cohosts Ryne Sherman, PhD, and Blake Loepp spoke with returning podcast guest Zlatan Krizan, PhD, professor of psychology at Iowa State University, about the psychology of nightmares.
As a child, Zlatan had a recurring nightmare of a gorilla coming down a hallway toward his bedroom. Within one of these nightmares, he eventually realized he was dreaming and decided to flee the gorilla by jumping out of his bedroom window. He woke up before he landed and never had the dream again.
This article covers what causes nightmares, what happens in the brain during dreams, the difference between nightmares and night terrors, and the impact of personality.
What Causes Nightmares?
Originally, the term nightmare was related to the experience of sleep paralysis. A nightmare was thought to sit on the chest and cause the feeling of being immobilized or suffocated. Today, the term is used to mean bad dreams in general.
“Nightmares are vivid, emotionally dysphoric dreams. They are dreams that tend to be very negative and are usually marked by emotions such as fear, terror, rage, or confusion,” said Zlatan. “Nightmares may wake you up because of the intensity of the emotional responses.”
Nightmares are common. Eighty-five percent of people report having at least one during their lifetime, and five percent report experiencing them weekly. When nightmares occur frequently, they can disrupt sleep and affect daily life.
So, where do nightmares come from? The brain—and our waking lives.
Zlatan described a study following the 1989 San Fransisco earthquake.1 Researchers compared nightmares occurring before and after the earthquake among people in San Francisco, California, and Tucson, Arizona. People in California had nightmares twice as often as people in Arizona after the earthquake. The closer they were to the epicenter of the earthquake, the more nightmares they had.
Events around us—especially extreme, unexpected traumatic events—drive the experience of nightmares. Nightmares seem to help us deal with emotional load and effective distress. They may also have a greater impact on daytime functioning and emotions in some people more than others.
Dreams and Personality
Personality doesn’t seem to affect the fact of dreaming. Sleep data show that nearly everyone dreams during REM (rapid eye movement) sleep. However, there are large individual differences in whether people remember their dreams, from hardly ever to practically every night. There are also individual differences in how bad dreams affect us.
Aside from traumatic life events, personality characteristics can make certain people more vulnerable to experiencing bad dreams. In terms of the five-factor model, the two personality dimensions that relate most to nightmares are (1) emotional stability and (2) openness to experience. “How sensitive are you to bad dreams? And to what extent would you be able to recall them in the morning?” Zlatan summarized.
People who score low in emotional stability are more likely to report nightmares with a lot of distress. This accords with their propensity toward negative affect, Zlatan explained.
People high in openness to experience are more likely to have frequent dreams in general. They are also more likely to recall their dreams and nightmares. Their imaginative characteristics allow their nightmares to cross from sleeping to waking, especially when associated with intense emotion.
What Happens in the Brain During Nightmares?
REM sleep is a phase of sleep associated with a lot of brain activity. Zlatan called it brain reorganization, saying that active areas when we are awake become less active and vice versa. During nightmares, brain areas associated with feeling emotions, identifying threats, recognizing conflicts or incongruities, and converting short-term memory into long-term memory are all active.
The visual cortex, which is responsible for processing visual information, is also active—but in an unusual way. “The first layer of the visual cortex that processes stimuli coming from the eyes is deactivated, which makes sense. Your eyes are closed. You’re not looking at anything. But the second layer is very active. It’s not processing images you’re seeing. It’s processing images that your brain is generating internally, which helps account for the visual nature of dreams,” Zlatan explained.
Recent theories about nightmares suggest that fear extinction may be a function (that is, eliminating fear-based reactions to negative experiences). Despite their unpleasant nature, nightmares can act as “overnight therapy,” a safe space to revisit bad things in novel ways. Another reason we have nightmares might be to process emotionally salient recent memories. Nightmares may also have a creative function because of the odd or illogical recombination of elements of consciousness.
Night Terrors Vs. Sleep Paralysis
Night terrors, which aren’t caused by dreams, tend to occur during slow-wave sleep when the brain is very unengaged. The sympathetic nervous system will trigger a physiological fight or flight impulse, a panic response, that causes you to startle awake. You might wake up confused, distressed, terrified, or even hyperventilating. Night terrors can relate to stress or anxiety, but they don’t necessarily have a psychological cause.
Sleep paralysis differs from night terrors. During REM sleep, we are actually paralyzed. Muscle atonia prevents us from getting up and living out our dreams, and a chemical called glycine blocks our body from responding to any nervous impulses coming from the brain. (People with REM behavior disorder aren’t paralyzed during REM sleep and tend to act out their dreams, which can cause injury.)
To transition from having dreams in REM sleep to being awake, several transitions must occur at the same time. When there is a delay in the restoration of movement, a person can be fully awake but briefly unable to move. “With sleep paralysis, that period gets elongated. You end up having a significant amount of time where in some ways you’re still dreaming, but in other ways you’re awake,” Zlatan said. Nightmares that occur during extended sleep paralysis can cause distress or panic. They often overlap visually with physical surroundings.
The experience of something dark and threatening, a figure that is menacingly but slowly approaching us, is universal in nightmares. The threatening figure might be a shadowy person wearing a hat, a fearsome animal, or a demonic spirit. Over time, the myth of the bogeyman, witch, or spirit is reinforced by stories and artistic representations. Even given cultural differences, the universality of fear underlies this concept. “I will leverage a hypothesis that that we had those experiences [of fear] first due to sleep paralysis,” Zlatan said. The vivid negative emotions, the overlay between the perceived environment and dream consciousness, and the helplessness of atonia—all make sleep paralysis nightmares particularly affecting.
How to Cure Nightmares
“There are usually layers of things that may be driving nightmares that come from life, history, or personality,” Zlatan observed. Other precipitating factors might be a recent stressful period of life. Physical triggers such as alcohol use can also cause nightmares. Stress management can help to lessen the intensity of distressing dreams so they don’t disrupt sleep.
For some people, frequent nightmares may be indicative of nightmare disorder, a type of parasomnia often associated with post-traumatic stress disorder. When nightmares are frequent, seeking medical treatment and therapy to address potential underlying psychological factors can help alleviate nightmares.
