Huge numbers of people are hiding mental health conditions from their employers because they fear it will affect their job, according to a new report.
More than one in four of those surveyed for insurance firm Friends Life said they had taken a day off sick, explaining it was for a physical rather than mental health problem.
The most common cause of stress was excessive workload, followed by frustration with poor management and long working hours, the study found.
More than half of those polled said their career prospects would be damaged if they were open about stress or anxiety.
Younger workers were more likely to suffer from depression, anxiety or stress, said the report.
Andy Briggs, group chief executive of Friends Life, said: "These statistics paint a worrying picture of a culture of silence when it comes to mental health.
"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."