Earlier this month, the typical media outlets were abuzz (“Childhood nightmares may point to looming health issues“) with the results of a newly published study linking early childhood nightmares and night terrors with future psychotic experiences. Expressing little in the way of skepticism, most reports simply regurgitated the University of Warwick press release. The research, published in the quite legitimate journal Sleep, is interesting but I’m not sure it tell us anything that we don’t already know. And it certainly doesn’t support any causal relationship between sleep disorders of any variety and “delusions, hallucinations, and thought interference”. But before we delve into the specifics of the paper, I believe a quick review of sleep, and sleep problems, in children is in order.
What is sleep?
To the outside observer, sleep appears as an altered level of consciousness where response to our environment and voluntary movements are noticeably decreased. But, with a certain degree of variability, the line between sleep and wakefulness is pretty thin. This distinguishes it from the increasing stimulation required to reverse other states of altered consciousness such as lethargy, obtundation, stupor and ultimately coma, which is not acutely reversible. I don’t plan on getting too technical, but there is obviously much more to sleep than that. Physiologically our metabolic demands drop a bit, and we enter a generalized anabolic or “growth” state during which a number of beneficial processes take place, predominantly, we think, involving the brain.
Sleep is a vital aspect of human life that has appears to have both physiological and psychological purpose, and is essentially universal in the animal kingdom. All you need to do is observe a cat for more than five minutes to see that we aren’t the only animal species that both needs and seemingly enjoys sleep. In fact, if you could talk to a nematode, it would likely go on for hours about how much it enjoys sleeping in on Sundays. Humans spend roughly a third of their lives asleep, but the percentage of each day devoted to sleep is significantly higher during infancy and early childhood.
We don’t know why the need to sleep became part of the blueprint for life so early on in our evolutionary history, and researchers certainly haven’t worked out all of the nuances of why humans and other animal species continue to be so dependent on it throughout the lifespan. It is likely that its purpose has broadened over time as species branched out into new environments. There are a number of leading hypotheses, however. And barring some amazing technological or medical advance, we appear to be stuck with sleep.