1 in 3 bosses cite mental ill-health as main driver of staff sickness

A YouGov survey, commissioned by Acas, asked 1,011 decision making employers what the top three reasons employees give for being off sick from work. The survey was undertaken in February 2026.

Almost two-thirds (62 per cent) said that minor illnesses, such as coughs, colds and the flu were the main reasons, while nearly a quarter (23 per cent) said that the absences are due to headaches and migraines. 

19 per cent said back pain and only 3 per cent said they would ‘prefer not to say’. 
Acas head of inclusivity, Julie Dennis, said: “Bosses need to ensure that their work environments are healthy places to work.”

“Workers should also look after their own health and wellbeing too. If they are experiencing stress, they should talk to their manager as soon as they can.”

Under new rules introduced by the Employment Rights Act 2025, workers will be eligible for statutory sick pay for their first day of illness. Photograph: iStock

Acas called the result "surprising", but the real surprise is that the research goes counter to recent reports that show employees are reluctant to tell their bosses if they are experiencing poor mental health. 

Over one in three (35 per cent) of workers said they did not feel comfortable discussing stress with their manager, according to this year’s Burnout Report by Mental Health UK. 

Almost a quarter (23 per cent) of employees would not tell their boss the true reason for being absent from work because they are afraid of being judged, found a survey by AXA PP Healthcare last year. 

Acas commissioned the study to highlight changes to statutory sick pay that will take effect in April. Under new rules introduced by the Employment Rights Act 2025, workers will be eligible for statutory sick pay for their first day of illness rather than the fourth day.

“Acas has good practice advice to help bosses manage sickness absence at work,” states the press release. “Providing training for managers on how to support employees through periods of illness can help with absence rates. Employers that offer flexible working can also help promote a healthy work environment and prevent high levels of sickness absence.”

For full survey results and guidance visit Acas here