Referrals to child mental health units from UK primary schools have risen by nearly 50% in three years, figures show.
Replies to Freedom of Information (FOI) requests from 46 health trusts indicate that referrals rose from 21,125 to 31,531.
Seven trusts said they had rejected an individual pupil for treatment at least five times over the last four years.
Pupils had spent more than a year on a waiting list for mental health services at 12 different trusts, according to the data obtained by the BBC.
Dr Bernadka Dubicka, chairwoman of the child and adolescent faculty at the Royal College of Psychiatrists, said the figures build on evidence which shows emotional disorders in children have increased in recent years.
“The government’s aim to provide mental health support in all schools within the next 10 years will be too little, too late for many children who need that help now,” she warned.
Head teachers told the BBC that some children are head-butting, punching and kicking walls.
BBC News also sent FoI requests to 500 primary schools in England about serious mental health episodes. It found that 191 primary school pupils had self-harmed on school grounds in the last four years, according to responses received from 155 schools.
These responses, and an account from a further school, also revealed that four pupils have attempted to kill themselves on primary school grounds over the last four years.
A government spokesperson said: “We are determined to improve mental health support for children and we are transforming services through the NHS Long Term Plan – backed by an extra £2.3bn a year – so that 345,000 more children and young people have access to specialist mental health care by 2023-24.”