The Chartered Institute of Personnel and Development found that one in four of 2,000 adults had experienced a mental health problem, sometimes caused by the stress of the job.

Government guidelines encourage those with a mental health condition who are finding it difficult to cope at work to talk to their employer.

But the CIPD found only one in four said that employers encouraged staff to talk about mental health problems.

Its head of public policy Ben Willmott said: "Managing mental health at work is central to good business performance.

"Stress is the number one cause of long-term sickness absence, but it is not just time lost to absence which impacts on the bottom line.

"Our survey highlights that the majority of people with poor mental health continue to attend work and report that it can impact on their ability to concentrate, make good decisions and provide effective customer service."

Mental health charity Mind chief executive Paul Farmer said: "This research shows that there is still a long way to go until workers feel able to discuss their mental health openly in work, enabling them to get the support they need.

"With one in four people surveyed having experienced mental illness this is an issue that will touch almost every workplace in the country."

The two organisations have published a guide aimed at helping employers support mental health at work.

Mind's campaign Taking Care Of Business: Mental Health At Work has pushed to increase mental health awareness in the workplace.

The charity says one person in six experiences depression, anxiety or stress during their employment.

Mind said a failure to address the problem increases isolation for mental health sufferers.

It warned that employers could be costing themselves up to £15.1 billion a year by failing to offer enough support to staff with mental health problems.

Further losses of £2.4 billion are caused by employees leaving their jobs due to mental illness - proof that ignoring the problem is a false economy, Mind said.

Mental health charity Rethink has produced guidelines on mental illness in the workplace for local authorities and the public sector.

The Department of Health said supporting a mentally ill person with their employment aspirations was a key part of the recovery process.

People who feel they have been discriminated against because of their mental health problems may have a case under the Disability Discrimination Act 1995.

Source: Will Stone, Health & Social Affairs Reporter, www.morningstaronline.co.uk

http://www.morningstaronline.co.uk/news/content/view/full/113306