The latest figures from NHS Digital show there were 6,500 days lost due to staff absence at Great Western Hospitals NHS Foundation Trust in February.
Of these, 1,400 were due to anxiety, stress, depression or other psychiatric illnesses, which accounted for 22 percent of staff sick days and were the most reported reason for sick leave.
This rate increased from 19 percent in February last year and 20 percent in 2019.
Across England, anxiety, stress, depression and other psychiatric illnesses accounted for more than 545,100 days lost and 26 per cent of all sickness absence in February, up from 25 per cent the previous year and 23 per cent in 2019.
Alex Baylis, from the King’s Fund health centre, said: “This is just another wake-up call for the NHS, because we are seeing exactly the same sort of trends when we look at the reasons why people are leaving the NHS.
“What we think is important is not just to focus on supporting individuals, but to look at what the underlying systemic factors are for these levels of stress and burnout.
“That means really listening to staff and being prepared to implement fundamental changes when necessary to address this, rather than normalizing it and continuing with these constant warning signs that we’re receiving.”
The figures also show that the overall sickness absence rate in England was five per cent, and four per cent in GWH.
The Nuffield Trust said high rates of sickness absence were damaging to staff and patient care.
Billy Palmer, senior researcher, said: “The NHS has a duty of care to its workforce, and this high level of stress among staff also points to some worrying retention issues in the future.
“With high levels of sickness absence and low retention both driving and contributing to increased pressure on services, the NHS is at risk of becoming trapped in a vicious cycle.”
She added that absence rates are linked to factors including job satisfaction, workload and socioeconomic status, so multiple solutions will be needed to address sickness absence levels.
A spokesperson for Great Western Hospitals NHS Foundation Trust said: “The very nature of a career in healthcare means that while it is often extremely rewarding, there are times when our dedicated staff are faced with difficult and emotional situations which can sometimes take their toll.
“While the Trust’s staff sickness absence rate due to stress is lower than the national average, and we have seen fewer staff absent due to stress in the months since February, we are monitoring the situation closely so we can assess the effectiveness of the measures we have in place and take steps to minimise the impact on our staff.
“The foundation offers a robust 24/7 health and wellbeing package for all staff, including counselling, trauma management, financial advice and bereavement support.
“Our Occupational Health and Wellbeing team and our 24-hour employee support colleagues provide support to any staff member who needs it, as well as working with managers to ensure a healthy work-life balance and other group wellbeing opportunities.”
An NHS spokesman said mental health support was available to staff, including access to confidential support services, counselling and flexible working options.
They added that “more needs to be done” to ensure NHS staff feel comfortable asking for help, saying: “That’s why the NHS is strengthening our occupational health services and reviewing our mental health offer for staff to ensure everyone working in the NHS has the right support they need.”
