Bad dreams can result from a variety of physical and psychological causes, and many of them tap into primal fears of predation.

Although there is still much about sleep and dreaming that remains to be discovered, research in the field has identifed the major causes of nightmares, as well as clarifying common misconceptions regarding bad dreams and sleep disorders.

Causes of Nightmares

The majority of people experience nightmares as a result of psychological problems, stress, trauma, illness or the use of drugs, alcohol or medication. The average is one to two nightmares per year, but approximately 5% suffer frequent nightmares. There are indications that those most likely to suffer from frequent nightmares are sensitive, trusting, open people. Some people experience nightmares as a result of eating certain foods or sleeping in certain positions.

The Myth of Dream Death

Despite a pervasive belief that if a person dies in a dream, he or she will die in reality, there is no basis for this. Plenty of people have died in their dreams without dying in actuality. Dreaming of death is thought to be a way of dealing with anxieties regarding mortality, rather than a prophesy of impending doom.

Good Dreams and Bad Dreams

Unfortunately, people tend to have more bad dreams than good ones. People dream about aggression more often than friendliness, misfortunate more frequently than good luck and negative emotions more than positive ones. Overall, approximately 64% of dreams are predominantly negative.

Types of Nightmares

Of negative dreams, about half involve being chased or attacked, while another 40% focus on a feeling of danger or witnessing someone other than the dreamer being injured or killed. These dreams tap into primal anxieties regarding predation, which were once very relevant but are now buried deep within the human psyche. In contrast to negative dreams, most positive dreams involve enjoyable pastimes, receiving a gift or having a desired possession.

Pregnancy Nightmares

A study of pregnant women found that at least 88% had regular dreams and nightmares about pregnancy and the time shortly after birth with their newborn babies. Common themes included an infant in danger (59% of pregnant women and 73% of new mothers). Pregnant women were also inclined to suffer nightmares about complications during childbirth.

Another common nightmare theme is that the baby has been lost in the bed. The mother searches through the bed sheets frantically but cannot find the infant. Many pregnant women and new mothers also dream about leaving the baby in a place or with a person and forgetting to pick her up.

Such nightmares among pregnant women and new mothers are perfectly normal and reflect common anxieties about the ability to be a good parent. The sleep deprivation suffered by new mothers may increase the likelihood of experiencing nightmares.

Sleepwalking

Contrary to popular belief, sleepwalkers are usually not dreaming (although those who talk in their sleep sometimes are). Despite the popular myth that waking a sleepwalker is dangerous, the opposite is true. Sleepwalkers need to be woken because they are likely to injure themselves. There have been cases of sleepwalkers driving cars while asleep, presenting a serious danger to themselves and others, and in one obscure case, a female sleepwalker found that she had been having sex with strangers in her sleep.

REM Sleep Behavior Disorder

REM Sleep Behavior Disorder (RSBD) is rare and most often afflicts elderly and middle-aged men. The sufferer is inclined to act out his dreams, with the risk that he may injure his bed partner. Unlike the normal dreamer, the RSBD sufferer is not paralyzed during REM (rapid eye movement) sleep when dreams occur. He will often have intense and even violent dreams, accompanied by kicking, punching and other aggressive actions.

Night Terrors

Often mistaken for nightmares, night terrors, which can be caused by stress, sleep deprivation, fever or certain medications, do not occur during REM or dream sleep. These episodes, characterized by intense fear and screaming or crying in sleep, affect up to 6% of children. Night terrors last for 1 to 30 minutes, during which the child appears to be awake but is unresponsive, and will not usually remember the episode upon waking.

Further Information

To read about the purpose of dreams, please see Why People Dream. To learn about differences in dreaming among men, women and children of different ages, see Gender, Age and Dreaming. For information about the meanings of dreams, see Dream Analysis and Interpretation.

References

• Doheny, K. (4 September 2007). "Bizarre Dreams Reflect Pregnancy Angst." WebMD Medical News.
• Hoss, B. (n.d.). “FAQ”. Dreamscience.org.
• International Association for the Study of Dreams. (2003). “Common Questions About Dreams” and “Common Questions About Nightmares.” Asdreams.org.
• Nowak, R. (15 October 2004). "Sleepwalking Woman Had Sex with Strangers." NewScientist.com.
• "REM Sleep Behavior Disorder." (Reviewed by Leonard Sonne, MD, 1 January 2007). WebMD.
• "Sleep Disorders: Night Terrors." (Reviewed by Leonard Sonne, MD, 1 January 2007). WebMD.
• "Sleepwalking." (2008). Yahoo! Health.
• The Dream Tree. (1998). “Famous Dreams & Dreamers,” “FAQs” and “Thoughts on Dreams.” Dreamtree.com.