Education Support's annual Teacher Wellbeing Index measures the stress, mental health and wellbeing issues reported by teachers and school leaders across the UK.
More than 3,000 education staff registered with the YouGov polling service responded to questions about their mental health and wellbeing between June and July this year.
The charity's findings suggest:
The report also used the Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS), which scores a person's wellbeing according to how often they report feeling optimistic, relaxed, or close with other people, for example. Those scores are then added together to give an overall picture of the respondent's mental wellbeing, with higher scores indicating a more positive mental outlook.
Compared with the general population, the teachers and school leaders who responded to the survey had a lower wellbeing score. The report's education staff wellbeing score was 43, compared with overall population scores of 51 in England and Northern Ireland, 49 in Wales, and 48 in Scotland.
The responses of more than a third (36%) of education staff produced a WEMWBS score of less than 41, indicating probable clinical depression.
Education Support chief executive Sinéad McBrearty said: "We urgently need a national retention strategy that puts staff wellbeing at its core.
"Without this, more teachers will leave the profession, and more children and young people's education will suffer."