More than 1,800 children aged under 10 have been hospitalised for self-harming in the past decade, sparking fears of a generation unable to cope with the pressures of childhood.
Last year alone almost 150 boys and girls aged 10 or under were admitted to hospital for intentional self-harm, including more than 80 pre-school children.
In a sign of a worsening problem, the number of girls and women aged under 25 admitted in the past 10 years has soared by 44 per cent to more than 26,270 in 2010-11. Among boys and men of the same age, the figure has leapt by a third to 11,656. The figures are for hospitals in England.
The Department of Health (DoH) admits that "only a fraction" of cases of self-harm are seen in hospitals, so the true scale of the crisis will be much larger.
"These shocking statistics should act as a wake-up call to everyone who cares about the welfare of young people," said Lucia Russell, the director of campaigns, policy and participation at YoungMinds, a charity which is working with the Government to redesign mental-health services for children. "Self-harm is often dismissed as merely attention-seeking behaviour, but it's a sign that young people are feeling terrible internal pain and are not coping."
According to officials, an episode of self-harm is often triggered by an argument or another upset, but can also be linked to bullying, low self-esteem, and worries about sexual orientation. The Government has promised £32m to improve access to psychological therapies for children and young people over the next four years.
Paul Burstow, a Liberal Democrat health minister, told The Independent on Sunday that, for too long, mental illness among children was overlooked by the NHS. "It has really suffered from being the poor cousin of mental health, which was itself the Cinderella service. It was not a priority for the NHS.
"For half of all mental health problems in this country the symptoms first show during adolescence. Let's look at the early signs and support families with proper therapies. It is about moving to intervene early."
More than one in 10 children aged 15 to 16 report having self-harmed in their lifetime. However, the DoH insists it is "rare for very young children" to self harm. A million children will have a diagnosable mental-health disorder. Childhood mental illness costs up to £59,000 per child every year.
The rise in hospital admissions has been steepest among women aged 17 to 25, rising by 50 per cent between 2001 and 2011.
Separate figures released last week show 40,000 under-25s were rushed to A&E in 2009-10 after self-harming, up from 36,000 in 2007-08.
Earlier this year, the Government launched a new strategy, No Health Without Mental Health, to tackle the problem. Officials are working with young people, parents and YoungMinds to redesign specialist services for children, focussing initially on cognitive behavioural therapy and parenting therapy.
Ministers hope to reduce by as much as 40 per cent the number of people in adulthood who have mental health problems. The economic and social costs of mental health in the UK are almost £100bn.
Last month a study by the charity Mind warned that a combination of rising demand and spending cuts was threatening the viability of mental health services.