Even Liam Fox, the Conservative health spokesman, has acknowledged that behavioural disorders indicate emotional difficulty, rather than incompetent teachers, impossible children or negligent parents.

But there’s an aspect of mental health, the perils of perfectionism, that has hardly been taken on board, except by some troubled teachers and a handful of psychologists. The relentless pressure on children - from parents, schools and politicians - to reach for the stars is creating a level of unhealthy perfectionism among even apparently successful pupils, such that their mental health could be undermined for years to come. Eating disorders, depression, self-harm and school absence are all rising, signs that all is not well.

If the cracks don’t appear at school, they often manifest at college. Last summer, in one small university town, a pathologist friend of mine was involved in three exam-related suicides, having not seen any in 14 years of practice prior to that.

With so much hype around success, and so much resting on young people’s shoulders, there’s a danger that more could become neurotic perfectionists or “success junkies”, dependent upon regular injections of achievement to keep the approval flowing and their sense of self-worth riding high.

In the United States, alarm bells are ringing. In 2000, a congressional committee found that the obsession with good results had led an estimated 20 per cent of college students to take Ritalin, the behaviour-modifying drug prescribed to calm hyperactive children. They steal or lie to get it, and take it to aid concentration and improve their scores.

Harry Lewis, dean of Harvard’s undergraduate college, has become so worried that last autumn he wrote to all students: “You may balance your life better if you participate in some activities purely for fun, rather than to achieve a distinctive credential for postgraduate employment. Many of the most important and rewarding things that you will do will be recorded on no piece of paper you take with you, but only as imprints on your mind and soul.”

Why can success backfire? The demand for ever higher targets and perpetual progress can tell children that no success is ever “good enough”. By celebrating success and ignoring failure, we may increase children’s anxiety; encourage them to invest their sense of self-worth in success and to become dependent on it; and, most important, lead children to sense that approval is conditional on their continued success.

Success does not invariably raise self-esteem: it depends on a child’s conviction that it can be repeated without undue effort and to what or whom they attribute that success.

Government plans to test, select and grade children as young as seven, mean the push for success will intensify. As soon as stars, medals or “gifted” labels appear, schools and parents want their children to acquire them, in part so they themselves may shine.

Surveys show that two-thirds of children consider they are under too much pressure to get good qualifications. American research confirms that what was considered an extreme anxiety level for children in the Fifties is now regarded as average.

Children who aim high, do well, and can sustain success in a healthy and balanced way, work to their own, realistic and flexible, standards and expectations. They can manage mistakes and failure. They tend to be well organised, have uncritical parents and strive because they enjoy the activity. They are in control. Most important, they have a robust self-esteem that doesn’t rely on proving themselves to others.

The seeds of unhealthy perfectionism take root where, to the child, approval appears conditional on success; where children strive to meet high and inflexible expectations; where adults “steal” any success; where no success ever seems good enough; where constant challenge generates constant doubt about ability; and where success is lauded and failure is shunned. Recognise it?

Elizabeth Hartley-Brewer is a freelance journalist and author of “Motivating Your Child”