Schools should not attempt to diagnose stressed children with mental health disorders, a Government adviser has said.

Tom Bennett, who guides ministers on behaviour issues in schools, warned that teachers must not give out “amateur diagnoses” to pupils, adding that there is a danger of “medicalising” normal childhood emotions.

His comments come as the Department for Education (DfE) publish new guidance on mental health and behaviour in schools, in which teachers are encouraged to refer children on to external specialists if they display symptoms of mental health issues.

“Schools need to be careful not to overreach their expertise and try to do the job of trained experts in the mental health arena,” said Mr Bennett, who was commissioned by the DfE to carry review behaviour policies in schools.

He said that teachers who tell their students that they are suffering from a mental health condition run the risk of exacerbating problems rather than solving them.

“If teachers try to be amateur diagnosticians, they can lead children to believe that their symptoms are something more serious. You can exacerbate stress by making people worry about it,” Mr Bennett told The Daily Telegraph.

“Teachers are not trained clinicians and schools need to be careful not to be amateur diagnoses. There is a danger of medicalising normal responses. If a child is stressed because of an exam or if a child is going through a bereavement that is not a mental health problem.”