Many children who take time off school with physical aches and pains are in fact suffering from anxiety and stress, according to an academic undertaking research in the field.
Marjorie Smith, of the Institute of Education in London, says many pupils who stay at home with debilitating head or stomach aches are transferring mental illness into physical pain. And if the condition is not treated early on, it can deteriorate to the point where it affects day-to-day learning.
Physical illness falls into two categories: symptoms stemming from a diagnosed cause, such as asthma, and those with no apparent cause, which can be influenced by psychological factors.
Physical, or somatic, problems are common among children and teenagers: 60 per cent of 11-year-olds reported having had stomach aches within the previous month, and half said they had suffered from headaches.
Many pupils also report an inability to sleep: some suffer from insomnia, while others take a long time to fall asleep or have recurrent bad dreams. This can then lead to problems with school attendance and performance.
The level of physical illness among pupils of all ages has risen over the past 30 years: one study reveals that headaches are five times more common now than in 1974. This could reflect the fact that emotional problems among the age group have become markedly more prevalent during this period.
The ways in which children cope with anxiety or stress influence how much physical illness they suffer.
Children who believe they can overcome emotional problems by searching for a solution are much less likely to become anxious, or to transfer anxiety into physical pain.
By contrast, those who do not believe they can tackle problems or adjust to accommodate them are the most likely to suffer from physical aches.
And children are far more likely to develop physical problems if their parents experience similar problems or suffer from anxiety.
In fact, says Professor Smith, parenting style is directly linked to the development of childhood anxiety and associated physical pain. For example, controlling parents shield their offspring from stressful situations.
Because they have not been encouraged to make their own decisions, children lack confidence in their ability to cope with daily life. Rather than believe they can overcome problems, they feel overwhelmed by them. They resort to wishful thinking, avoidance and denial as means of distancing themselves from their problems.
"Children who react to stresses with pain symptoms," said Professor Smith, "have been shown to have less confidence in their ability to overcome the situations or events that they have found difficult in their daily life."
Teenage girls are far more likely than boys to adopt such maladaptive coping strategies. Girls are also much more likely than boys to report physical problems.
While the occasional headache or stomach ache rarely disrupts pupils' learning, these conditions can escalate if left untreated. Studies also suggest that children with physical symptoms will continue to experience these into adulthood. They are also at greater risk of suffering psychiatric problems in later life.
"So intervention and treatment are important, to prevent the development of future chronic conditions and more serious psychiatric problems," Professor Smith said.
"The aim of prevention would be to improve emotional health ... by reducing the frequency and severity of any physical symptoms or feelings of anxiety. This would include improving social competence and coping, such as developing problem-solving skills."
HOW SCHOOLS CAN HELP
Physical symptoms of anxiety and stress are best tackled in school, according to Professor Smith.
Intervening at school, she says, is relatively cheap, and avoids the stigma of mental health clinics. It also allows the problem to be tackled directly in a place where children often experience anxiety.
Including all pupils in the intervention programme avoids the stigma of singling out specific children and can help develop a positive culture throughout the school.
But such programmes may be too short or superficial to help those children who are already developing problems.
Programmes to promote mental health in schools also tend to focus on preventing bullying or substance abuse rather than on tackling anxiety or depression.
Research suggests that short-term preventive programmes targeted at particular groups of children are far more likely to produce long-term benefits. But these require sufficient time, facilities and trained staff.
"It is not feasible to expect important behavioural and cognitive life skills to be absorbed within a single intervention programme," Professor Smith said.