More than a third of GPs have cut their hours in the last year, with many blaming the demands of the job, according to a new report.
An annual workforce report from the General Medical Council (GMC) found high numbers of GPs at risk of burnout, high levels of dissatisfaction and more than one in 10 GPs taking time off in the last year due to stress.
Almost one-fifth of GPs said they were considering leaving medicine entirely in the next year, the report found.
The study also found GPs inappropriately referring patients to hospital while stressed out by a high workload, and patients suffering harm due to pressures on the system.
The study found:
The number of GPs is growing faster than the UK population, but 46% of GPs are contracted to work less than full time, and 36% have reduced their clinical hours in the past year, with many citing stress.
Two thirds (65%) of GPs work beyond their contracted hours every day - double the 32% of NHS doctors overall.
Some 17% of GPs feel unable to cope with their workload everyday - also higher than for doctors overall.
GPs said the demands on them included increasing numbers of patients, more complex cases and unrealistic expectations from patients. Some patients were unrealistic about what the GP could do, or made inappropriate visits, such as for head lice.
Half of GPs feel satisfied in their work while 45% are dissatisfied, higher than the 30% of doctors overall who are dissatisfied. Reasons for dissatisfaction included bureaucracy, increasing time constraints and working in conditions that are "unsafe" for patient care.
Almost a quarter (24%) of GPs gave responses that suggested they were at high risk of burnout.
Half of GPs were found to be in the "struggling" group, working over their contracted hours at least weekly and feeling unable to cope at least weekly. By contrast, only one out of 10 GPs are in the "doing well" group, compared with almost a third of doctors overall.
Some 92% of GPs have felt unable to provide patients with a sufficient level of care at least occasionally during the past year, and more than a quarter (27%) of GPs felt this way every day.
Women are more likely to work part-time as GPs - 61%, compared with 26% of men. However, 79% of male GPs aged 30 to 49 said they were considering reducing their hours in clinical practice in the next year.
Almost a fifth (18%) of GPs are considering leaving medicine entirely within the next year, around a third of whom were considering retirement.
35% of doctors said they have made a patient referral which was not strictly necessary due to pressures on their workload over the past year. A quarter of GPs did this at least once a month.
The report said: "An increase in referrals leads to more patients in the system, which leads to bottlenecks in services and longer waiting times.
"By unnecessarily adding more patients into the system, it creates more demand for a health service already stretched and struggling."
The study included responses from 3,876 doctors, including 1,079 GPs.
GMC chief executive Charlie Massey said: "Ensuring doctors have supportive and compassionate workplaces is vital and will be the focus of much of our work in 2020.
"But the incoming Government must also listen to, and act on, concerns that are being raised by us, employers, patients and doctors."
Suzie Bailey, director of leadership and organisational development at the King's Fund (a health charity that aims to shape health and social care policy), said: "Staff shortages in the NHS are creating a vicious cycle of increased pressure on doctors, nurses and allied health professionals, which in turn leads to more of them choosing to reduce their hours or leave their profession altogether."
Professor Martin Marshall, chairman of the Royal College of GPs, said: "It's not surprising to see more GPs reducing or planning to reduce the number of clinical hours they work.
"They shouldn't be criticised for this - it's this flexibility in working patterns that general practice offers that makes the job sustainable, so that GPs and our teams can continue to deliver safe care to a million patients a day across the country.
"The reality is that working 'part time' in general practice often means working what would usually be considered full-time, or longer - our own research shows that almost 80% of GPs work longer than their contracted hours at least once or twice a week.
"Working 'full-time' in general practice is simply not doable for many, and this is causing GPs to burn out, or leave the profession earlier than they planned to because they feel they cannot guarantee safe standards of care for their patients.
"It makes sense that GPs are making choices about their career to safeguard against this."