A third of secondary teachers in an Edinburgh University study were suffering levels of depression and anxiety similar to those of clinical psychology outpatients.
The research showed that 90 per cent of those surveyed thought the profession had become "quite a lot more" to "very much more" stressful in the past five years.
Fourteen per cent - made up of 18 class teachers and 40 middle managers - reported particularly high levels of stress that might need therapeutic intervention.
Indiscipline was seen as the main source of stress; 62 per cent of teachers said this was a chief cause. More than half the respondents also blamed an excess of paperwork and lack of time.
The research, based on a survey of 407 teachers in 18 schools, was presented by Edinburgh Univer-sity's Rosie Mulholland at the annual conference of the Scottish Educational Research Association. But she cautioned that the results were based on self-reporting, and that the survey took place in April 2003, a particularly pressured time in the school year. In addition, all who took part chose to do so; the teachers surveyed represented a 68 per cent response rate.