Performance targets, curriculum changes and heavy workload are harming the mental health of teachers in England and Wales, a study suggests.
Researchers who interviewed 39 teachers from across the country found evidence that "managerialism" in schools was causing stress and mental health problems.
Many of the teachers believed that having to focus on targets and results was fundamentally altering their role as educators and undermining the pupil-teacher relationship.
Teachers spoke of disillusionment, loss of self-esteem and failure, leading some to take early retirement, said the study authors.
One had attempted suicide because of pressure at work.
Teachers 'face unrealistic expectations'
A large proportion of survey participants, who had all experienced long-term sick leave, felt they were under constant scrutiny and pressure to perform to "unrealistic expectations".
Most thought they were failing the children in their care and themselves by no longer being able to encourage active learning.
Lead author Professor Gerry Leavey, of Ulster University, said: "The destruction of self-esteem and effectiveness, combined with the despair of an externally constructed failure, permeated most of our interviews with teachers.
"Their comments express a tension between the old view of what it means to be a teacher – commitment, service to the school and pupils' learning – and the new managerialist view: accountability, performativity and meeting standards in a new, corporate world.
"This tension is often internalised and impacts on teachers' identity. It often pits taking care of themselves and the non-academic needs of pupils against management duties and targets.
Promoting teacher wellbeing
"Too often, this leads to stress and mental health problems. Too many good teachers are leaving the profession through ill-health."
Dr Barbara Skinner, an educationalist at the university, said: "Educational reforms, and the rigidly prescribed organisational and management structures that accompany them, should be weighed against their impacts on professional identity and personal wellbeing.
"We also need better evidence-based interventions to promote teacher wellbeing."
The researchers also spoke to six headteachers, deputy heads and assistant heads who had dealt with mental health problems among their staff.
The DfE has been contacted for comment.
The findings have been published in Educational Review.