Nearly a quarter of staff absences in the Royal Devon University Healthcare Foundation Trust over the past year were stress-related, new figures show.
Health think tank The King’s Fund said staff shortages across the NHS must be addressed to ease stress and heavy workloads.
NHS Digital figures show there were roughly 51,200 full-time equivalent days lost due to stress-related absences in the year to June at Royal Devon University Healthcare NHS Foundation Trust – accounting for 22.7% of the total 225,600 days lost.
It is up slightly from 22.5% of staff absences in 2021-22.
The figures cover all professionally qualified clinical staff, clinical support staff, and infrastructure support staff who were absent due to anxiety, stress, depression or other psychiatric illnesses.
Alex Baylis, The King's Fund assistant director of policy, said the Health and Safety Executive has found health and care staff consistently report higher rates of work-related stress. He added a key cause of this stress is "chronic excessive workload".
He said: "Workload pressure can particularly come from things like working extra hours, or managing a higher number of patients, because of staff shortages.
"It can build up if that’s the situation day after day. And it can be exacerbated by things like working across chaotic teams or processes, not having the equipment that’s needed, not having breaks, or unsupportive managers."
While leadership at team level is essential in supporting staff, Mr Baylis added the overall NHS staff shortages must be addressed.
"Although everyone wants to reduce the current long waiting times as quickly as possible, that must not override the need for a culture of supportive management and supervision," he said.
Across all NHS England organisations, 6.1 million FTE days were lost to stress-related staff absences. They made up nearly a quarter (23.9%) of all days lost in the year to June.
It is relatively in line with the year prior but down significantly from 27.7% in 2020-21.
Overall, 25.5 million days were lost to staff absences in 2022-23, marking a fall from 26.6 million days the year before.
Dr Billy Palmer, Nuffield Trust senior fellow, said the high sickness absence rate in the NHS adds to costs and disruptions to care.
"If staff who are off sick cannot be covered by temporary staffing, this has a direct impact on those receiving care, and those stuck on waiting lists waiting for care."
He added: "The level of staff sickness related to mental illness, anxiety and stress, which are bundled together in this data, is a troubling indicator of the pressure being experienced by NHS workers."
A Department of Health and Social Care spokesperson said: "We are hugely grateful to NHS staff for their hard work and their health and wellbeing is of paramount importance.
"For those staff that need it, the NHS provides physical and mental health support – including targeted psychological support and treatment."
They added the Long Term Workforce Plan, backed by £2.4 billion in Government funding, focuses on recruiting and retaining more staff to make the NHS the "best place to work".