Average burnout scores among GPs are higher than those for any other medical specialty other than emergency medicine, according to research published in BMJ Open.
The study into resilience, burnout and coping strategies among UK doctors found that in addition to high burnout scores, 'compassion satisfaction' scores among UK GPs were lower than those for any other specialty.
Compassion satisfaction measures pleasure derived from being able to do your job - and low scores on this measure have been linked to burnout.
GP leaders called the findings 'alarming' and warned that they underscored the need for a rapid increase in funding and measures to bolster recruitment and retention of doctors.
RCGP chair Professor Martin Marshall said: 'GPs and our teams are at the front line of delivering patient care and demand for our services is escalating, so it isn't surprising that this research has found that we, alongside our colleagues in emergency departments, are most at risk of burnout.
'Workload in general practice is rapidly increasing in terms of volume and complexity, yet the resources we have to deal with this are inadequate and the numbers of fully-qualified, full-time equivalent GPs working in the NHS is falling. This situation is leading to many GPs burning out and leaving the profession earlier than planned.'
BMA chair Dr Chaand Nagpaul said: 'These findings are alarming and strongly reinforce precisely what the BMA has been saying for a long time.
'Years of systemic underfunding and serious workforce shortages mean NHS doctors are working longer hours in highly pressured, understaffed environments, and their wellbeing is suffering as a result.'
The researchers said that ideally doctors should score low for burnout and stress, and high for compassion satisfaction - but only 6% of respondents fell into this category.
They added that the most common coping strategies cited by doctors were self-distraction or self-blame - suggesting doctors were struggling to cope.
The researchers wrote: 'Doctors cannot be expected to recover from the emotional stress and adversity they encounter in their role as clinicians while managing a heavy workload in an under-funded, over-worked system.
'It is unlikely that emotional resilience is all that is required to cope with increasing regulation, litigation, and administration.'
Professor Marshall added: 'Particularly at a time when more patients are living with multiple, long-term conditions, the standard 10-minute consultation is increasingly unfit for purpose, yet offering longer consultations would mean offering fewer, and many GP practices are already booked up weeks in advance.
'We need to see effective retention strategies being implemented nationwide to keep GPs in the profession longer – and reducing what has become an "undoable" workload is key to ensuring that more experienced GPs can have sustainable careers in the NHS, both delivering safe patient care, and mentoring the next generation of GPs.'