Why Children Have Nightmares

Remember some of the nightmares you used to have as a child?

According to the American Academy of Sleep Medicine, children between the ages of five and ten seem especially prone to having nightmares which are often vivid enough to be remembered years later. In sleep surveys of American adults, 75 percent of the general population reported remembering at least one vivid nightmare they experienced during childhood. Despite how common nightmares are in children though, there have been surprisingly few research studies into how and why these nightmares occur.

Though there have been numerous studies looking at nightmares, they have almost all focused on adults (probably because they are easier to study). Based on these studies, certain key factors have been identified that seem to play a role in the kind of nightmares adults have. They include:

• Posttraumatic stress. Not surprisingly, most people dealing with some form of posttraumatic stress disorder are going to report nightmares, whether of the traumatic event itself or some other nightmare scenario that produces the same sense of fear and helplessness associated with the original trauma.
• Anxiety. Whether related to trauma or not, anxiety about problems experienced in waking life are going to shape the kind of dreams you may have. This includes worrying about finances, issues at work or school, social fears, etc.
• Dissociation. We are all detached from reality to some extent no matter how down-to-earth we believe ourselves to be. During sleep however, the things we prefer not to think about while awake can often come out in the form of nightmares. This also suggests a potential reason why nightmares can be so vivid in children since they have greater difficulty separating fantasy from reality.
• Physiological changes. Researchers have used different physiological measurements to study sleep disturbances and how they could be related to nightmares. One physiological index that seems to be especially useful in predicting nightmares is heart rate variability (HRV), or the variability in the time intervals between heart beats. Not only does HRV measure the body's ability to adjust to stress, but it seems far more sensitive than more traditional measures of bodily changes such as heart rate. People with a high HRV rate seem much more flexible and adaptable in dealing with stress or anxiety. On the other hand, victims of trauma often have a much lower HRV rate than normal. While one study has found a significant link between HRV and nightmares for adults and adolescents, the reason for this link is still hard to understand.

But do these same factors apply to the nightmares experienced by children? A study published in the journal Psychological Trauma suggests that they can. Led by Marie E. Secrist of Alliant International University in San Diego, a team of researchers recruited 60 children, aged 6 to 11, along with one parent each from the San Diego area to take part in the study. Two-thirds of the children in the study were boys and children on psychotropic medications such as Ritalin were dropped. The participants were recruited through local churches, referrals by local pediatricians, or online advertisements. Parents were rewarded for their participation with a $20 payment while the children were rewarded with a toy they could pick out.

For the children in the study, all assessments took place either in their home or in a local library to make them feel more comfortable. As their parents completed questionnaires, the children spent five minutes on an exercycle before having their heart rate variability measured. The children were then questioned directly about how often they experienced nightmares and how frightening these nightmares were. The children also completed a test measuring overall level of anxiety.

The parents in the study completed questionnaires measuring the sleep habits of their children and dissociative symptoms shown by children (such as inability to separate fantasy from reality). They were also questioned about demographic information as well as whether their children experienced any prior traumas and had anxiety symptoms.

Overall, the results were somewhat skewed in terms of how many children reported nightmares. More than half (58 percent) denied having any nightmares while 23.3 percent reported one or more nightmares a month. Still, there were 11 children in the study (19.4 percent of the total) who reported three nightmares or more a month. There were no real differences between these different groups in terms of trauma history or anxiety though parents rated children experiencing one or more nightmares a month as being more prone to dissociation.

Still, while trauma history, anxiety, dissociation, and heart rate variability didn't appear to have a strong influence on how frequently children had nightmares, they did appear to influence how much distress these nightmares caused. When combined in a multiple regression design, all four variables accounted for as much as 39 percent of total variance in nightmare distress, a highly significant result. Of the individual factors, dissociation seemed to play the strongest role in the amount of distress children reported.

This result doesn't seem so surprising, considering previous research has already shown that people high in dissociation tend to experience situations more vividly, immerse themselves more deeply in emotion, and have more distinct memories than low-dissociation adults. Since children typically recall vivid nightmares more frequently, they are far more likely to be remembered even years later.

Another factor that seemed to play a role in nightmare distress is generalized anxiety. Children with increased anxiety tend to report more distressing nightmares which, along with trauma history, could make children more prone to "sleep terrors" which only go away when they become adolescents.

As for physiological factors such as heart rate variability and sleep quality, they seem to play an important role in predicting mental health problems such as depression or poor emotional control. HRV may also be linked to resilience since children with low HRV are much more prone to nightmares and trauma.

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Though more research is needed, this study shows how trauma, anxiety, and other mental health issues can influence how often children experience nightmares as well as why they can be so distressing. New treatment approaches for reducing anxiety and dissociation, as well as biofeedback techniques to increase HRV may help children avoid the distress such nightmares often bring.

If, as Alexander Hemon once said, your nightmares follow you like a shadow, forever, helping children get these nightmares under control may be the key to a healthier life.