As a paediatrician who works with many children with these problems - constipation can account for 25 per cent of referrals to paediatricians - I believe there might be considerable overlap. We know that stool withholding is common among children; some hold on for days, even weeks. Indeed, "constipation" in childhood is usually a misnomer; the child invariably is trying to stop a stool rather than pass it. This is often linked to a fear of going to the toilet, perhaps because, when they do go, it hurts. A vicious cycle develops, because the longer the stool is held, the harder it becomes and the more painful when it emerges. The longer each cycle continues, the more concentration and energy are required simply to stop the stool coming.
This is made worse by knowing that as time progresses, the feared passing becomes imminent and inevitable. Stool withholding requires self-discipline and control. Most people would find it a challenge to hold on for three days; many children that we see can hold on for three weeks. They adapt their posturing - standing rather than sitting, for example - and become distracted. Concentration and learning suffer. On a smaller scale the child who is desperate to go, but waits till they get home, is also likely to be fidgety and distracted. Sometimes there will be soiling. A similar problem occurs with urine. Children often wait until the last minute; again, trying to concentrate when they are bursting is next to impossible.
These problems are likely to be most noticeable in the afternoon, and can be compounded by mild dehydration. Children rarely drink enough at school, certainly less than the recommended three to four glasses of water a day.
Drinking fountains provide so little at a time that children can need umpteen visits to get the equivalent of one glass. Schools that encourage drinking report a marked improvement in behaviour.
So, a school where children drink enough and feel comfortable going to the toilet will reap the dividends. But there are other issues. One of the challenges of toilet training is teaching anticipatory voiding: making children understand that they "don't have to be bursting to go". Teachers see breaks as a chance to go to the toilet, while children call them "play time" and do not want to lose out . It is disruptive when half the class asks to be excused as soon as break is over, but it is also difficult to get children to change their behaviour.
Much of the above is being championed by ERIC (the Enuresis Resource and Information Centre) in two campaigns, Bog Standard and Water's Cool in Schools. But I worry that they will not have their maximum impact unless the link between these issues and education is fully understood. If you still have doubts, next time you really need to go to the toilet, wait, sit down with an article from the newspaper. Read it through and then go. How much do you remember and how still did you sit?
Anthony Cohn is a consultant paediatrician at Watford and Hemel Hempstead hospitalsSee The issue: water, page 11