UK employees are continuing to hide mental health conditions from their employers in fear that it will damage their career prospects, findings from Friends Life reveal.
The survey of 2,000 employees found that four in 10 individuals had suffered from stress, anxiety or depression in the last year but failed to tell their employer.
More than a quarter of respondents to the survey said they had taken a sick day claiming it was for a physical problem when it was for a mental health issue.
Over half of those questioned felt being open about stress or anxiety with their employer would damage their career prospects.
Friends Life group chief executive Andy Briggs said the statistics painted a "worrying picture" of the culture surrounding mental health in the workplace.
"Our research shows that there is still much to be done in tackling mental health issues in the workplace. Anxiety, stress and depression can affect anybody and employees need help and support so that they are not left feeling vulnerable and demotivated."
The most common cause of stress in the workplace according to respondents was excessive workload, followed by frustration with poor management and working long hours.
Younger workers struggled most with mental health issues in the workplace, with almost two thirds of 18 to 24 year olds agreeing that they had experienced stress, anxiety or depression in the last year, compared with just over one third of those aged 55 and over.
Business in the Community workwell director Louise Aston warned that the costs for employers of mental ill health were "too great to ignore".
"This research demonstrates the damaging culture of silence that currently exists around conditions such as stress, depression and anxiety in UK workforce," she said.
"People are afraid to speak out and this requires urgent action from business leaders. We need to see more organisations encourage an open-dialogue and offer proactive interventions that promote mental wellbeing, so that employees can seek the support they need without fear of stigma or reprisal."