Nightmares can be triggered by medications, oddball genes, degenerative neurological diseases like Alzheimer’s, last night’s tamales, traumatic events in the present, never-healed wounds from the past that a recent event has unmasked, and gut-level threats to health, safety, and the very sense of who you are.
Those who put a lid on expressing how they feel in response to stressful events during the day are likely to be taken for a ride by those emotions in the form of nightmares at night. And some, particularly people who are open and sensitive, may have a “thin” boundary between what’s real and what’s a dream—which means that their waking life is more than likely to stir up their night life and cause some pretty hairy dreams.
“A nightmare is a dysfunctional dream,” explains Rosalind Cartwright, Ph.D., director of the sleep disorder service at Rush-Presbyterian-St. Luke’s Medical Center in Chicago. Instead of integrating the day’s events and feelings with older, stored memories and defusing negative emotions—which is what some researchers feel a dream is supposed to do—the emotions your brain is processing overload your circuits, prevent their integration into older memories, and jerk you from sleep.
If you’re in a bad car accident, for example, you may not be able to process all the negative emotions the accident generates right away, says Dr. Cartwright. The fear and your sense of vulnerability and mortality are overwhelming. So you may have nightmares for a while as your mind keeps working away at integrating your feelings. Once it does, however, the nightmares go away.
As Dr. Cartwright eloquently writes in her book Crisis Dreaming, “Nightmares are a cry for resolution for finding a way to incorporate the terrible experience into our lives. Occasional nightmares are normal,” she adds. “But not nightly, and not over and over again.”
When Nightmares Are a Sign of Danger
“Major depression usually wipes out dreaming altogether,” says Dr. Cartwright. “Depressed people usually have no recall of dreaming, no dream content, no story. If they do, it’s very short, very bland, with no feeling at all.
“As they recover from depression, however, their ability to dream comes back, and their dreams get more elaborate and full of emotion.” Unfortunately, those recovering from depression can sometimes overshoot and be flooded with negative emotion.
“That’s when suicides can occur,” cautions Dr. Cartwright. So it’s very important that anyone who is depressed report nightmares to their doctor immediately.