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Up to 50% of children between 3 and 6 years of age, and 20% between 6 and 12 years experience ‘frequent’ nightmares (American Psychiatric Association, 2000; Nielsen et al., 2000; Siegel, 2009). Fisher et al (2014) reported that the persistence of nightmares during the preschool and school years (2.5 to 9 y of age) was associated prospectively with psychotic experiences at age 12 y. This association held regardless of family adversity, emotional or behavioral problems, IQ, and potential neurological problems. Nightmares and bad dreams tend to persist in some children. Simard et al (2008) reported that mothers’ ratings of their children’s bad dreams indicated prevalence of frequent bad dreams at 1.3% to 3.9%. The best predictor of having a bad dream at 5 and 6 years of age was their earlier presence at 29 months. Questionnaire based nightmare and bad dream studies typically show that nightmare frequency is highest between the ages of five to ten, and is related to other sleep disorders, trait anxiety, emotional problems, and behavior problems later in life.
Despite the huge prevalence of bad dreams and nightmares in kids and the very well documented associated of these nightmares with distress and ill-health for these kids later in life, there is very little funding for or research into children’s sleep and dreams. To my knowledge there have been no longitudinal studies of sleep/dreams processes and nightmare emergence and maintenance in children. The last longitudinal study of children’s dreams was done in the 80s in Europe and in the 1970s-80s in America. Neither of these studies addressed nightmare mechanisms and both were arguably at least partially flawed. For example, in the Foulkes’ study (Foulkes, 1999) the author did not get any clear or extended reports of dreams from kids until middle childhood –yet every parent knows that kids as young as 2 can report dreams. They are therefore best considered to be initial forays into the issue of children’s sleep and dreams and the relation of children’s sleep and dreams to their daytime functioning.
The Fisher et al., finding noted above that persisting nightmares in early childhood can predict psychotic experiences in later childhood is a particularly important finding in my view. Similar relationships obtain between recurrent nightmares in adults and an array of neuropsychiatric disorders. So in my view there may be a causally potent relationship between nightmares and psychiatric disturbance. Why then might nightmares be mechanistically related to neuropsychiatric disturbance?
The common view is that nightmares result from emotional trauma and emotional trauma is the ultimate cause of psychiatric disturbance. But many people experience intense or severe emotional trauma and never develop psychiatric disturbance. Some scientists think that psychosis is in essence the irruption of REM dreaming into waking consciousness. The neurochemistry of REM sleep mimics in some ways the neurochemical aberrations associated with psychosis. But there is only equivocal evidence of intrusions of REM sleep into waking states in patients with schizophrenia who are also experiencing hallucinations. Another possibility is that nightmares represent a failure in the memory consolidation process and it is that cognitive dysfunction which explains the emergence of psychosis. If there are frequent repeated nightmares then the consequences of the memory dysfunction grow over time until the system is chronically overloaded with a backlog of memories still waiting to be integrated into long term memory stores. That backlog of unintegrated memories in turn represent cognitive loss for the individual as he or she has to operate in the absence of the information contained in those memories. The backlog furthermore has to “hang out” somewhere in the cognitive system and they very likely use up precious and scarce cognitive resources and interfere with other ongoing cognitive operations. Now when the recurrent nightmares occur in childhood when the child is in school and attempting to learn all kinds of new information the inability to acquire new memories and to integrate new information into the cognitive system is going to be catastrophic. So it is crucial to do something for these children as soon as nightmares become “frequent” At the very least we need to initiate new longitudinal studies of normal dreaming and abnormal dreaming in children.
References
Fisher H, Lereya ST, Thompson A, Lewis G, Zammit S, Wolke D. Childhood parasomnias and psychotic experiences at age 12 in a UK birth cohort. Sleep 2014; 37: 475–82. [PMCID: PMC3920312] [PubMed: 24587569]
Foulkes, D. (1999). Children’s dreaming and the development of consciousness. Cambridge MA: Harvard University Press
Nielsen TA, Laberge L, Paquet J, Tremblay RE, Vitaro F, Montplaisir J. Development of disturbing dreams during adolescence and their relation to anxiety symptoms.
Sleep. 2000 Sep 15;23(6):727-36. Review.
Simard V, Nielsen TA, Tremblay RE, Boivin M, Montplaisir JY. Longitudinal study of bad dreams in preschool-aged children: prevalence, demographic correlates, risk and protective factors. Sleep. 2008 Jan;31(1):62-70.
Siegel, A., (2009). Children’s Dreams and Nightmares: Emerging Trends in Research Dreaming. Journal of the Association for the Study of Dreams: Special Issue: Children’s Dreams and Nightmares: Emerging Trends in Research. Washington DC: American Psychological Association. Vol 15 3 (2009)147-154.
