A survey by the British Medical Association (BMA) found 80 per cent of respondents were at high risk of burnout and more than 25 per cent have been diagnosed with a mental health condition.
One in three used alcohol, drugs, or prescription medication as a means of coping, said the BMA, which carried out a survey of 4,300 doctors and medical students in the UK.
The doctors' union has called for action to tackle unmanageable workloads among medics and more access to mental health support.
Professor Dinesh Bhugra, BMA president, said: “The findings speak for themselves. With four in ten of the respondents surveyed currently suffering from depression, anxiety, burnout, stress, emotional distress or another mental health condition, and an overwhelming eight in ten of those surveyed at high risk of burnout, the enormous demands being placed on doctors have come at a worrying price.
"As the people who are entrusted with caring for the health of others, doctors often feel particularly vulnerable or unable to come forward and seek help for fear of judgement and or any perceived ramification a declaration of poor mental health may have on their prospective career.
“A system that fails to support and protect the health of its own workforce will only flounder and this is as clear a call to action if ever there was one.”
The BMA survey found that 27 per cent of respondents had been diagnosed with a mental health condition at some point and seven per cent were diagnosed in the past year.
Some 40 per cent reported suffering from "a broader range of psychological and emotional conditions". Those working 51 hours a week or more were most likely to be experiencing problems.
The BMA's report said: “Ninety per cent of respondents stated that their current working, training, or studying environment had contributed to their condition either to a significant or partial extent;
“In primary care, half of GPs said they or their practice had sought help or support for a condition affecting their work or training.
"While the majority of respondents said they did not use alcohol, drugs, self-medication or prescribing as a way to cope with a mental health condition, one in three said they used it regularly or occasionally."
Men and older doctors were most likely to engage in substance misuse to cope with their problems, the research found.
A Department of Health and Social Care spokesperson said: “Doctors are the backbone of our NHS, providing excellent, safe care to patients around the clock.
"They deserve our unwavering support and as part of our long term plan for the NHS, the upcoming People Plan will lay out the actions we will undertake to overhaul the mental health and wellbeing support on offer for all NHS staff.
“Alongside the BMA we recently announced improvements to shared parental leave arrangements for doctors, part of our commitment to improve working conditions make the NHS an employer fit for the 21st century.”