About one in 20 people in the workplace suffer from a depressive illness. Depression costs Irish business £170 million each year in lost work days.

"It feels like you're stuck underneath a scrum. But you don't know when it'll get off you. You're feeling suffocated and freaked out. Just powerless," says a 25-year-old construction worker who suffers from depression.

He admits to "very low self-esteem" even though intellectually he knows there's no reason for it. He fears his employer might see him as a liability if he knew but he has told his foreman and a workmate.

When he is well he is an excellent worker. But when depressed his motivation collapses. He is unable to relax or think straight and he gets severe anxiety attacks. Moreover, he can take things personally: "Someone says boo to you. You take it the wrong way. It echoes around your head." He finds himself "loosing the rag over nothing". His self-esteem plummets "like an uncontrollable force telling you you're worthless".

But mostly it doesn't affect the quality of his work. He says: "Because someone's depressed doesn't mean they're a health hazard. Those who get depressed are more likely to do a good job than those who are carefree. They're that bit more in touch with themselves."

A successful journalist who suffers from mild depression is least depressed at work: "My problem is when I'm not working. At holidays work gets stripped away. What's left? Self-loathing usually happens when I'm not active. Holiday times are risky.

"I got a panic attack last Christmas. I got pretty down. It was over a trivial thing. I'm not good at technology. I get nervous. I seemed to have wiped something out. I was in a sweat.

"It went from `I can't solve this problem' to `I'm useless at technology' to `I'm useless at the modern world.' " But luckily he had to attend a meeting and work drew him back from the abyss. Five minutes into the meeting he was fine.

Dr Patrick McKeon, consultant psychiatrist at St Patrick's Hospital, Dublin, and chairman of Aware, the depression awareness group, says people who get depressed can give a business a tremendous advantage because they tend to be more hardworking and conscientious than others.

Because they undervalue themselves, they tend to commit themselves thoroughly to work to prove their value. The astute personnel department should view any reference to depression as a possible boon to a company rather than a black mark against the candidate.

Indeed in certain sectors like the creative arts or graphic design, says Dr McKeon: "If you want people who are creative, you can't have one without the other." He says employers "can't be better off without them" and argues for the active management of depression in the workplace.

Employees tend to hide depression from their employers. They fear being stigmatised. But he says an employee's fear is often not based on reality.

They can be surprised to discover that their condition is not stigmatised even if some employers have a "one-dimensional, stereotypical view of it".

He knows of instances where "out of naivety or courage" candidates tell a potential employer and they get the job for being upfront.

But a recent study he carried out found that "depressed employees tend to conceal their condition from their employer". It found that 72 per cent of out-patients at a mood disorder centre gave their employer a medical rather than a psychiatric sick note.

Mr Brian Glanville, director of psychology with the EHB says that work culture doesn't encourage people to come forward with emotional difficulties: "People don't feel safe doing so for at least some good reason." But he says often there isn't sufficient reason. "Often a perception grows up that it's risky. But the reality might have changed since the belief began."

Ms Una Halligan, public affairs manager at Hewlett-Packard says the firm emphasises well-being. "We encourage employees to tell us if they're not happy. We look at the whole person." She says there's no reason for employees at Hewlett-Packard to feel apprehensive about revealing depressive conditions. It carries no stigma.

Mr Peter Rowlel, human resources specialist at Boston Scientific in Galway, says the company is working with Aware to manage depression in the workplace. "We hope to be seen as a caring employer. You have to trust the organisation."

He says he has had instances of employees who told him they can't come to work because they're depressed. They didn't feel the need to hide it behind the smokescreen of some physical complaint.

Dr McKeon believes it would be a very healthy thing if all workplaces could adopt that approach.