Twelve young people in Britain commit suicide every week, according to the latest figures from the Samaritans.
The suicide rate is now three times higher than that of 20 years ago, and this week academics told The TES that schools are not doing enough to help pupils or to stop them self-harming.
Researchers from Surrey university say that not all schools have systems in place to deal with pupils' depression before it spirals out of control.
They visited schools across the country to find the best initiatives for dealing with vulnerable youngsters and have written a book about their findings.
They say that many schools fail to provide adequate help.
Professor Helen Cowie, one of the four co-authors of Emotional Health and Well-Being, said: "We are not saying teachers should become psychiatrists, but schools need to create a supportive, helpful environment in which young people know where to turn in difficulty. Some schools are doing sterling work but it is not all that widespread."
Last year, 759 children and young people telephoned Childline to say that they had attempted or were thinking about commiting suicide. A further 1,475 phone calls were about depression, and 1,122 about incidents of self-harm.
The Samaritans took 2.5 million calls last year, and email contact from the young is increasing. A spokeswoman said: "Society needs to take more responsibility for opening up about emotions. It is hard to point the finger of blame at schools. The fact is, mental health is not a sexy subject and many young people may be reluctant to talk about it."
A study by the mental health group Young Minds in 2002 found that in a school of 1,000 pupils, there were likely to be 50 with serious depression, 100 in a distressed state, up to 20 with an obsessive-compulsive disorder and 10 with an eating disorder.
Professor Cowie said: "People should take on board these issues long before a child is referred to counsellors or psychiatrists - that goes for families and the community as well as teachers.
"An awful lot can be done to prevent breakdown as many schools have demonstrated."
She said this could be achieved through peer-support networks, reward schemes and by teachers spending more time listening to children's problems.
Her comments follow calls from Margaret Hodge, the children's minister, for children to be given psychological counselling in schools.
Chris Keates, acting general secretary of the National Association of Schoolmasters Union of Women Teachers, said that in the past responsibility had fallen to teachers, but the workforce agreement meant there is now capacity for other adults to take on the role.
Part of the Surrey university research was funded by the Department for Education and Skills and is expected to be released in a separate government document.
* The Samaritans launched a resource pack for schools last year to advise teachers about pupil depression and other mental health issues. For more details, see www.samaritans.org.uk