The study, published in the BMJ Open journal, found that over a quarter (26%) of doctors under official investigation by the GMC or subject to complaints procedures reported moderate to severe depression.
Researchers from Imperial College London surveyed almost 8,000 doctors and found that four in five doctors admitted they acted more defensively and changed the way they treated patients as a result of complaints against themselves or a colleague.
The vast majority (84%) said the ordeal caused them to become overcautious, making them more likely to overprescribe, refer too many patients or order unnecessary tests. Just under half (46%) felt less confident in taking on difficult patients or procedures.
By inducing psychological ill health and encouraging defensive practice among doctors, the complaint system is likely having knock-on negative effects on patients as well, the researchers said.
Almost two in five (39%) doctors said they felt bullied as they went through the complaints process, while 20% felt the complaint against them was a direct result of them being victimised after whistleblowing.
2013 saw the GMC receive more than 8,500 complaints against doctors, but less than half (3,000) went on to be investigated. Around 80 doctors a year are suspended or erased from the medical register.
Professor Tom Bourne, lead author of the study, said: ‘Of course it’s essential that when things go wrong, the reasons are properly investigated.
‘But this study suggests that the regulatory system we have in the UK has unintended consequences that are not just seriously damaging for doctors, but are also likely to lead to bad outcomes for patients. We think this needs to be looked at carefully by policy makers.’
BMA chairman Dr Mark Porter, said there were ‘growing concerns’ over how the complaints process was affecting doctors.
‘It is in the interests of both doctors and patients that, where appropriate, concerns can be raised and that these are properly investigated. But this process must be fair and offer adequate protection to ensure the system itself does not cause harm – either to doctors or indeed to patients.’
GMC chief executive Niall Dickson welcomed the study, which he said contributes to an ‘important and difficult issue’ which the regulator is ‘actively addressing’.
GMC 'actively addressing' problems
He said: ‘We have a duty of care to these doctors. That is why we are doing more than ever to reduce the stress of our investigations, by offering support and doing everything we can to reduce the time doctors are in our processes.
‘Since 2012 we have introduced a new support service run by the BMA for any doctor in our procedures, we are referring less serious complaints to be dealt with locally, we have introduced meetings with doctors to resolve cases more quickly and established the autonomous Medical Practitioners Tribunal Service which is also taking steps to speed up the process.’
Last month, the GMC called for medical students to receive ‘emotional resilience’ training after it reviewed all deaths of doctors in fitness to practise cases and identified 28 suicide cases.
In October last year, a poll by the Medical Protection Society found that three quarters of doctors reported a negative health impact after a GMC investigation.