July 26, 2000 -- Most everyone has experienced nightmares or bad dreams ranging from being chased by something scary to standing naked in public. What researchers in Montreal have found is that these nighttime dramas happen more often than previously thought, and their impact may be greater than suspected.
The Association for the Study of Dreams (ASD) says the dreamer may feel any number of disturbing emotions in a nightmare, such as anger, guilt, sadness, or depression, but the most common feelings are fear and anxiety.
While nightmare themes may vary widely from person to person, the ASD says probably the most common theme is being chased. Adults are commonly chased by an unknown male figure, whereas an animal or some fantasy figure commonly chases children.
In a Montreal study -- which appeared in the July edition of the Journal of Abnormal Psychology -- a nightmare was defined as a scary dream that caused the person to wake up as it occurred. A bad dream, on the other hand, meant the person remembered his frightening dream but didn't wake up as a result. But there's an even greater difference between the two. "Nightmares adversely effect well-being more than bad dreams do," Antonio Zadra, PhD, psychologist and professor at the University of Montreal, tells WebMD.
Zadra says that although bad dreams and nighmares happen more frequently, memories of bad dreams and nightmares fade away over time. To prove this, Zadra and his team of researchers recruited over 80 students majoring in the arts, science, and engineering who were asked to recall how many bad dreams and nighmares they'd had over the previous month, and also the previous year. They were also given daily dream logs to record their dreams of all types during the four-week study.
More than 80% of the students reported having at least one bad dream over the four weeks of the study. During the month prior to the study, only 69% reported having a bad dream. The number of bad dreams reported for the previous year was also significantly lower.
Although nearly half the students reported having a nightmare during the four-week study, only 33% recalled having one during the month prior to the study. Again, the one-year totals were even lower than the one-month totals.
Prior to beginning their daily dream logs, the students also completed a study to measure their well-being, including their level of anxiety and depression. "We found that the more frequently a person had nightmares, the lower his sense of well-being," Zadra tells WebMD. "We found they were more adversely affected by nightmares than bad dreams, although bad dreams affected them also, just not as much."
In the June 1994 edition of Dreaming: Journal of the Association for the Study of Dreams, Carrie Bearden, PhD, reports there are three primary categories of nightmares, all of which are related to increased brain activity:
- Chronic, lifelong nightmares that are phenomena of personality
- Traumatic nightmares related to post-traumatic stress disorder
- Drug-induced nightmares
Zadra says that from his research he was able to pick apart a theory surrounding bad dreams and nightmares -- that women suffer more from them than men. "That's a myth. Women are more likely to talk about them, and to volunteer for studies. However, in a random sampling, nightmares occur in equal proportion between men and women." In the Montreal study, 68 of the 89 participants were women.
Causes of nightmares may vary based on age and gender of the affected person. According to the NIH Sleep Research Coordinating Committee, some common causes include:
- Illness with a fever
- Death of a loved one
- Anxiety or stress
- Adverse reaction to or side effect of a drug
- Recent withdrawal from a drug such as sleeping pills
- Effect of alcohol or excessive alcohol consumption
- Abrupt alcohol withdrawal
- Eating just prior to going to bed, which raises the body's metabolism and brain activity
According to the NIH, nightmares tend to be more common among children and decrease in frequency toward adulthood. In children, the content of the nightmare may be influenced by daytime experiences such as television viewing, movies, or frightening real-life events. In adults, there is a less specific association between nightmares and daytime events. Occasional nightmares without other symptoms are common and usually don't require treatment.