Teachers are seeing more pupils in the classroom with mental health issues, according to a poll.
It reveals that half of teachers have seen an increase in youngsters dealing with difficulties such as anxiety, depression, ADHD, hyperactivity, eating disorders, substance misuse and self-harm than they did two years ago, while around 60% have seen a rise compared with five or ten years ago.
The survey, conducted by the Association of Teachers and Lecturers (ATL), suggests that just over two fifths (43%) of those questioned say that between 10% and 25% of pupils in their school or college have mental health issues.
More than a third (37%) said this figure was less than one in 10 students, while 14% put it at between 25% and 75%.
The findings come just days after Education Secretary Nicky Morgan announced new measures - including funding and guidance for schools - designed to change the way children and young people suffering with these problems are supported in and out of the classroom.
Figures show that one in 10 children - equivalent to three in every classroom - have a diagnosable mental health disorder, Mrs Morgan said, insisting that there "must be no trade-off between learning about mental health and academic success."
ATL's poll, which questioned over 850 education workers, found that around two thirds (65%) believe that their school or college is having to provide more support to pupils with mental health issues because it is needed, while a further 23% said there has been a slight increase in the level of support needed.
Many believe that cuts to Children and Adolescent Mental Health Services (CAMHS) are to blame for making it difficult to get help for children in difficulty, ATL said.
Some 43% said that their school or college is finding it much harder to access mental health and social services compared with two years ago, with 18% saying the level of access is the same, 5% saying it is now easier and 34% saying they don't know.
One head of department at a Reading secondary school told the union: " "CAMHS is completely overwhelmed. Unless there is significant risk of harm to either the child or others, there is pretty much no point contacting them."
Nearly half (48%) said that the procedures in place at their school or college are adequate to deal with mental health problems among pupils.
But the poll also found that over half (59%) do not feel that enough time and resources are devoted to tackling these issues in the place where they work, with 23% saying these are adequate.
ATL general secretary Dr Mary Bousted said: " It comes as no surprise that so many education professionals are feeling so utterly let down on all sides when it comes to support for children's and young adults' mental health. The systematic stripping away of social services and CAMHS funding by the current Government has left pupils dangerously at risk and, once again, it has been left to school staff to plug the gaps in social care as best they can.
"The latest announcement of an extra £1.25 billion for CAMHS over the next five years, while welcome, smacks of closing the stable door after the horse has bolted. Before it pats itself on the back, the Government might want to look at the circumstances that can induce poor mental health, such as poverty, poor housing, unemployment and financial insecurity."
The union is due to debate a resolution calling for mental health support for pupils at its annual conference in Liverpool next week.
It calls on the union's executive to lobby government to invest in preventative measures such as safe havens for vulnerable children in schools and appropriate funding levels for dedicated staff.
:: ATL's survey, conducted this month, questioned 861 union members working in schools and colleges in England, Wales, Northern Ireland and the Isle of Man.
A Government spokeswoman said: "Mental health problems can be a real barrier to children reaching their full potential. Many schools are already doing excellent work in improving pupils' well-being, but we want to do more to help them address the challenges children face head on.
"Teachers can raise awareness of mental health issues in PSHE lessons and the curriculum gives them the freedom to address any specific issues that meet the needs of their pupils - but they are not mental health professionals and they need to be able to get support from specialists.
"The Government is providing £1.25 billion of new funding over the next five years to treat 110,000 more children with mental health issues. We are also setting in train a brand new series of actions, including greater use of counselling in schools, improving teaching about mental health, and supporting joint working between mental health services and schools as part of a fresh focus to ensure children can thrive and live life to the full both inside and out the classroom."