Imagine yourself in the moment between realising you are falling and hitting the ground. Think about how that feels. Imagine the moment when you reach into a pocket or bag for your wallet and realise it isn’t there any more. Imagine the panic, the fear, the gnawing sickness that erupts within you. Your heart thuds and your breathing becomes faster.

Now imagine that same feeling persisting for days, weeks, months or even years.

That’s how many people with anxiety disorders describe their experience. And if the headlines of the past few years are to be believed, this is what more and more of our schoolchildren are feeling every day.

Earlier this year, the children’s charity Barnardo’s released the results of a survey showing that nearly half of all 12-year-olds feel sad or anxious at least once a week; the total rises to 70 per cent by the age of 16.

Meanwhile, calls to the NSPCC Childline service, asking for help with anxiety, are on the rise: between 2015 and 2016, the total jumped by 35 per cent.

That’s just two surveys among many. Add up all the surveys, anecdotes, school reports, teacher testimonies and expert opinions, and the case for there being a serious problem with anxiety among young people seems compelling. But what might be behind it?

The most commonly cited explanation is the current education system. Exams. Tests. High-stakes accountability. A system, according to critics, that turns humans into numbers and child development into data - an environment in which schools are little more than grade factories.

But is any of that true? Are we really watching a childhood-anxiety epidemic caused by education unfurling before our eyes? Worryingly, we may not actually know.

Anxiety is a feeling of worry or fear that manifests itself in negative thought patterns (“What if I fail my exams and my life is ruined?”), which interfere with concentration, focus and sleep. There may also be physical effects, such as a racing heartbeat, sweating, and feelings of sickness or dizziness.

These symptoms are caused by the release of adrenaline - the “fight or flight” hormone produced in response to real or imagined threats.

Unwelcome inheritance

While all of us get nervous or stressed from time to time, some people find themselves trapped in a spiral of worry that leads to chronic anxiety. And the likelihood of that happening to you is partly genetic, argues Eleanor Leigh, a clinical psychologist at the University of Oxford’s Centre for Anxiety Disorders and Trauma.

“A third to a fifth of the variance in anxiety problems in the population can be explained by genetic inheritance,” says Leigh. And while there aren’t any specific “anxiety genes”, there certainly are genetic variations that influence how our brains are wired up and how sensitive our bodies are to the effects of adrenaline.

“Children come into the world with behavioural temperaments to a greater or lesser extent, and that affects how they learn about their environment and whether they’re likely to go on to develop anxiety problems,” she adds.

As well as nature, there’s also nurture. For example, overcritical and controlling parenting is associated with anxious behaviours in children. Major life events, such as bereavement, accidents, abuse and sexual assault all add to the mix, as does bullying and the effects of an unsettled or unhappy home life.

Measuring the prevalence of anxiety is difficult. It’s possible to count the number of referrals from GPs to child and adolescent mental health services (Camhs) for severe anxiety, although these services are increasingly stretched; a 2016 study showed that up to 61 per cent of children and young people referred to Camhs did not then receive treatment.

Much less is known about how many children are going undiagnosed, or aren’t being referred onward for help. Studies of self-reported anxiety from mental health charities can fill in some of the gaps, but it’s much harder to find hard data about the true scope of anxiety in the general population due to a lack of long-term research.

From the figures we do have, though, there is little sign of anxiety being at the epidemic level that some are claiming, says Leigh.

“We’re lacking really good long-term data on the changing levels of anxiety in children and young people, but the information we do have doesn’t point to an epidemic,” she states.

The most reliable data at the moment comes from the Next Steps study, formerly known as the Longitudinal Study of Young People in England, which uses the fairly blunt measure of psychological distress rather than specific disorders, such as anxiety or depression. The most recent results were gathered in 2014 and show a slight increase in distress in girls, but no significant overall rise in the number of young people reporting clinically relevant levels of distress.

“While there might be a growing number of children seeking help - which might be from increased public awareness about anxiety - it isn’t sufficient to say that there’s an increase in the baseline rate,” says Leigh. However, she does acknowledge that changes in policy and social media are happening so rapidly - during the past decade, in particular - that it’s hard to know for sure that things have not worsened since 2014.

“The past 10 years have seen monumental changes in the lifestyles of young people, and we don’t know what the long-term consequences of that will be,” she says.

Certainly, surveys of young people are clear that, since 2014, more children have been reporting that they feel anxious. Teachers, Camhs and mental health charities all say they have seen more incidences of anxiety than ever before. And last month, health secretary Jeremy Hunt asked chief medical officer Dame Sally Davies to review the effects of social media on the mental health of young people, and signalled that legislation to ensure their wellbeing was one possible course of action.

Social media is making the spread of unhealthy behaviours easier, argues Tara Porter, a child and adolescent clinical psychologist based in north London.

“Mental health problems are a bit like measles - they can be contagious,” she explains. “If you have a big social media group that children join, such as one of these big WhatsApp groups, you only need one person to have mental health problems and be posting about suicide and self-harm to provoke a wave of distress. Self-harm used to be quite a rare component of mental health, but now it’s extremely common among children and adolescents.”

Some academics are willing to go on the record to suggest that there has been a likely increase in levels of anxiety.

Paul Stallard, professor of child and family mental health at the University of Bath, leads the child and adolescent mental health research group. He told Tes in November that “it’s difficult to know with any certainty whether there are more mental health problems today than there were a decade ago. But we do know that more children are seeking help from online counselling and telephone helplines, and we know the rate of self-harm in young people is increasing…Although we don’t have the definitive evidence, there do seem to be a lot of child mental health problems out there at the moment.”

Examining the issue

Likewise, David Putwain, an educational psychologist at Liverpool John Moores University, suggests it does seem that there has been an “increase”. So, if that rise has in fact occurred, do we know with any certainty what might be causing it?

Teaching unions, charities and many teachers are clear that the main culprit is the exam system. And students are self-reporting that exam stress is a key component, too.

Putwain agrees that exams are certainly part of the problem. “Talking to leaders and teachers, they see the government reforms that came to fruition in 2014 as being behind all this,” he says. “For GCSE students, we’ve moved from a modular approach, including coursework, to a system of big, terminal exams at the end of two years. It focuses everything into one nub right at the end, and the volume of exams that has to be done in a three- or four-week period adds to that pressure. It would be wrong to say this is the entire cause, but it seems to be driving an increase in anxiety.”

Putwain also points to the wider message that today’s students are receiving about education: in a highly competitive global economy, their grades are the only things that matter. “We’ve had successive governments assuming a neoliberal approach, applying the ideas of free markets, such as choice and accountability, to education in a rather brutal fashion,” he says. “It starts with Sats in primary school and is pervasive throughout the culture. Children internalise the message that to be a good person they must achieve and do well in their exams. I’ve met young people who are very eloquent in their disassembling of that narrative, but there aren’t many.”

Leigh, however, doesn’t believe that the increased number of - and emphasis on - exams themselves is a major cause of anxiety.

“I think it’s the other way round,” she says. “We know that kids with anxiety disorders and learning difficulties find school and exams hard already, so there’s going to be an extra burden on kids who are already struggling, by making them do additional exams. So we can say that lots of exams are difficult for kids with anxiety disorders. But we can’t say what impact frequent exams will have on mental health outcomes for other kids.”

As Leigh mentioned earlier, genetic and environmental factors are hugely influential on anxiety; separating those elements from exam anxiety would be difficult.

Stallard also cautions against too readily pointing the finger at exams. “There are the usual suspects - anxieties about school and academic performance, as well as fitting in with friends socially,” he says. “But children also have anxiety from the use of social media, constantly monitoring who is doing what, and worrying that they’re not involved. Instant access is also an issue - so much is visible online, and if you don’t have an immediate, positive response, it gets you worried.

“We’re also seeing more children who are worried about terrorism and nuclear war, stories in the news about places like Syria, or are concerned about fires after the Grenfell Tower incident. They’re exposed to much more information about the possibility of bad things happening, feeding into concerns that the world is an unsafe and dangerous place, and they get very anxious about it.”

This is not to say that education is not a factor, says Leigh. She notes that the messages schools are giving to students can still have an effect.

“Teaching, as a profession, has become a very burdensome job in terms of admin and performance expectations - a lot of stress in teachers comes because their career is dependent on the results of their students, so messages might be coming through to young people about the importance of succeeding,” she says. “For kids that are already predisposed to anxiety, that could reinforce that negative message and create more.”

So, we have no reliable data about the perceived increase in the incidence of anxiety, nor conclusive proof of what’s causing it.

But, it seems, there is some evidence telling us that children are feeling more anxious and that exams are playing a part in that.

One obvious question is: aren’t exams supposed to be a bit stressful? Isn’t a degree of anxiety a good thing? “We know that a bit of stress is good - it gets you focused, pumped and ready to go,” says Leigh.

Physiological studies show that the fight-or-flight adrenaline rush triggered by a stressful situation - such as an exam, sporting race or musical performance - helps to boost performance by increasing blood flow to the brain and muscles, heightening the senses and bringing a sense of focus. But the balance can easily tip from helpful boost to crippling hindrance in people who are more susceptible to adrenaline’s effects, and who may already be stuck in patterns of anxious thinking.

What about those who claim that all of this recent “anxiety” is down to delicate kids being incapable of processing normal levels of stress due to overprotective parenting? That narrative, says Putwain, is based on an inaccurate perception of what children are now going through. “The problem is that we all base our views on our own experiences, not what’s happening now,” he explains.

“But the schooling system children go through now looks nothing like the one I went through as a pupil, nor the one I worked in as a teacher. People, including policymakers, naturally reflect on what things were like when they were at school, but we need to talk to students and teachers today because they’re the ones that are living it.”

He adds that it is a false argument. No one is claiming exams are not going to be stressful, he says, but rather that they can be too stressful for some children. “Exams are supposed to be stressful, but for a certain proportion of people, high exam anxiety is as significant as clinical anxiety,” he says.

To understand why this might be the case, Putwain points to the underlying psychological processes going on when a pupil prepares for an exam. “The first question a student asks themselves is ‘Is this important to me? Is this valuable to me?’ And if yes, then they ask ‘Am I any good? Am I likely to pass?’ If the answers to both questions are yes, then they’re likely to do well. If they think it’s important, but lack confidence and think they won’t pass, then that’s where anxiety and disengagement come from.

“Changes to exam structure and the world we live in now are magnifying the importance and value of every test, raising the stakes in the minds of students.”

‘Look out for the quiet ones’

The problem with a lack of hard data about anxiety and the narrative of the “snowflake generation” is that it provides an opt-out from doing anything about anxiety levels among children - at both a policy and a personal level. But absence of evidence is not evidence of absence. Clearly, children are reporting feeling anxious, and that alone should be cause for action, even if it is to tell some of those children that the stress they are feeling may be normal or even helpful. And those who genuinely do have a problem need support, says Leigh.

“You need to look out for the quiet ones,” she suggests. “It’s often not the kids who are causing trouble, shouting and storming out of the room - it’s the ones you might not see. The children who don’t ever put their hand up, don’t ask questions, speak in a whisper, might lock themselves in the loo or have a lot of sick days with things like tummy aches.”

If that sounds like one of your pupils, the last thing you should do is confront them when there’s anyone else watching, she warns. “If you do approach them, be sensitive,” urges Leigh. “Ask about it in a way that’s normalising - ‘Do these feelings ever come up for you?’ - allowing the door to be open, and giving the message that it’s always OK to ask for help and advice without feeling forced to talk.”

For more severe anxiety, a GP can refer a child to the local Camhs, although waiting lists are long and the service is stretched. Charities such as Childline, YoungMinds and Place2Be can also offer support. And there’s plenty that school staff can do to help.

We also need to ensure that some general rules are followed with all children, says Leigh. “We can shape the messages that teachers and parents give to students,” she says. “There could be a shift in terminology and maybe we need to focus on effort rather than outcome. We could reintroduce pride in working hard, doing your best, and focusing on learning for curiosity’s sake.”

Putwain believes that a number of schools are already taking action. “Some schools are putting on workshops for coping strategies to deal with the pressure, based on ideas of resilience and other techniques like yoga, breathing and mindfulness,” he says. “Others have peer ambassadors, such as sixth formers, that worried GCSE students can talk to.

“The key thing is raising it up the school’s agenda to ask which resources and expertise they have to draw on.”

Whether or not you believe that we are amid an anxiety academic, taking measures to relieve the pressure on all young people seems advisable; the effect of mental health problems on children’s wellbeing is too serious to ignore. Up to one-in-five adolescents may experience a mental health problem in any given year, and many are not getting the help they need. You won’t always spot them.

If it is possible to avoid piling unnecessary pressure on children, then that would clearly be a very good idea, regardless of the academic arguments around prevalence and causes on anxiety. And there’s one crucial point that many anxious pupils would benefit from being told. “Children already feel under an incredible pressure and have no sense of freedom,” says Porter. “More work isn’t always better. Some young people need to have fun, laugh more and learn to let go.”

Dr Kat Arney is a science author and broadcaster. She tweets @Kat_Arney