Thursday, October 28, 2010

Things That Go Bump in the Night, Part 3

At last we have come to the final and arguably the most frightening stop on our terrifying tour of sleep disorders. Part 1 (fatal familial insomnia) threatened to keep you awake. Part 2 (sleep paralysis and night terrors) was almost guaranteed to cause nightmares. I shall leave it up to you to deduce the effect that Part 3 will have on your circadian rhythm and overall metabolism. Brace yourself for the horror of…

It was a dark and stormy night. The boy awoke and instantly sensed that something wrong. Very wrong. He tried to calm himself, searching his mind for a rational explanation. Perhaps it was rain seeping in from an open window. Perhaps he’d stirred in his slumber and knocked over a glass of water on the nightstand. The window, however, was firmly shut and there was no evidence of a glass anywhere. Slowly he realized he knew what wicked thing had caused this. It was the same evil that had stalked him for as long as his memory could record. It had tracked him down even after his family had moved to a new house in a new town. It was nocturnal enuresis. He had wet the bed.

The details of the protagonist in my ghost story were chosen not just to demonstrate that the tale was not an autobiographical one, but also to set up the demographics of the affliction. As with the more glamorous parasomnias discussed in Part 2 of this series, nocturnal enuresis, the polite term for bedwetting, is more common in childhood than in adulthood. It is also more common in males than in females. DSM-IV * defines nocturnal enuresis as urinating in bed past the age of 5 years, at least twice a week and without any known provocation.† The condition is generally further divided in 2 subcategories – primary, in which the patient has never achieved nighttime bladder control for any length of time and secondary, in which they managed 6 or more “dry” months before the problem recurred.

Bedwetting runs in families and several physiological factors have been suggested as causes. One is insufficient nighttime production of arginine vasopressin (AVP). AVP is a hormone that helps regulate water within the body. Its release causes less water to go into urine, which of course results in a lower volume of urine. Ideally, thanks to circadian rhythms, the body produces more AVP and thus less pee at night.‡ Lower nighttime AVP production and subsequent higher urine volume has been documented in some children suffering from enuresis.

Another physiological difference between bedwetters and non-bedwetters may be how easily they wake during sleep. For a lighter sleeper, a full bladder would provide ample physical stimulus to rouse them from sleep. Heavier sleepers are not always so fortunate. We should take a moment to note the difference between “heavy sleep” and “deep sleep”. Deep sleep refers to slow-wave sleep, stages 3/4, which you may recall from last week’s discussion of night terrors. Heavy sleep simply indicates that it would take a great amount of noise, light or discomfort to wake a sleeper. The sleep patterns of enuretic patients are no different than those non-enuretic ones. Those who suffer from nocturnal enuresis do not spend more time in deep sleep, they are just potentially harder to wake from any sleep stage.

Environmental and social factors also play a role in bedwetting. Those exhibiting nocturnal enuresis often hale from larger, less stable, and more financially disadvantaged families. Divorce, especially during the critical toilet training years, can often precede the onset of bedwetting. However there is little evidence that any of these factors actually cause nocturnal enuresis rather than merely aggravating it in those who are already physiologically predisposed toward the condition. Plenty of people experience difficult childhoods and never wet the bed.

At this point I could tell you about behavioral and pharmaceutical treatments for bedwetting, but it being so close to Halloween I prefer to discuss serial killers and something called the “McDonald triad”. The triad was proposed by its namesake J.M. McDonald in 1963 in an attempt to predict future violent behavior based on traits exhibited in childhood. He noted that 3 such traits were often found in psychiatric patients with violent tendencies. The triad consists of firesetting, cruelty to animals and bedwetting.§ Now while burning down houses and kicking puppies is the sort of thing one expects to find in the childhood of a violent criminals, the third item is a bit harder to fathom. Why bedwetting? When I first heard of the triad I (insensitively) joked that wetting the bed must be the ultimate sign of disregard for society and its rules. More realistically it may just be another symptom of the stress of an abusive upbringing (also quite common to violent crime). And humiliating experiences themselves are another frequent occurrence in the life histories of serial killers. Bed wetting certainly comes with its share of social stigma. Not to say that all children who wet the bed will grow up to be multiple murderers. However if your child has taken to peeing in their bed after already exhibiting the other 2 behaviors on the checklist, now may be the time to start sleeping with your bedroom door locked.

That’s all I have for you on this sleep disorder. I need to finish my Halloween costume now, and I owe you a new species of the month for November. Happy Halloween!

* DSM is short for the Diagnostic and Statistical Manual of Mental Disorders. It is a 5-axis system for attempting to describe the spectrum of human psychiatric ills and is the accepted diagnostic tool of most U.S. mental health workers. The thick and expensive book is published by the American Psychiatric Association. The most recent edition, DSM-IV-TR, came out in 2000 and DSM-V is set to hit the stands in 2013. If anyone wishes to pre-order the book for me, I will gladly spend a post or two comparing it to the previous edition, which by that time I should be able to get on eBay for a few bucks plus shipping.

† Illness, medication side effects, having a sibling put your hand into warm water, etc.

‡ The benefit of channeling less of the body’s water into urine production at night is not just the prevention of enuresis, it also protects the sleeper from dehydration by conserving water at a time when none is likely to be ingested.

§ Future research did not always support the McDonald triad, but it was catchy enough to remain in the folklore of psychology, where I originally heard of it. In the articles I read, bedwetting did, however, emerge as the most consistently-correlated to crime of the 3 traits.

Who told you this?

Laberge, L. et al. 2000. “Development of Parasomnias From Childhood to Early Adolescence.” Pediatrics 106: 67-74.

Butler, R.J. 2004. “Childhood nocturnal enuresis: Developing a conceptual framework.” Clinical Psychology Review 24: 909-931.

Nappo, S. et al. 2002. “Nocturnal enuresis in the adolescent: a neglected problem.” British Journal of Urology International 90: 912-917.

McKenzie, C. 1995. “A Study of Serial Murder.” International Journal of Offender Therapy and Comparative Criminology 39: 1-10.

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