It is the illness that dare not speak its name. Now, no less a figure than Antonio Horta-Osorio, appointed in a blaze of publicity to guide the part state-owned Lloyds Banking Group back to health, has been forced to take a leave of absence because of it. The bank's terse statement to the stock exchange merely said that its chief executive was temporarily stepping back "due to illness", but it is understood that the cause of this is stress and exhaustion, brought on by working round the clock, seven days a week. Ironically, the news came on National Stress Awareness Day.
The "temporary leave of absence" recommended by medical staff has left the bank in turmoil, not least because Tim Tookey, the finance director who will serve as acting chief executive for the next two months or so, is to quit for a high-profile job in insurance in February. There was scant sympathy for Mr Horta-Osorio in some City quarters, where brutal work schedules are commonplace. But it is not the first time a public figure has been forced by stress or exhaustion to quit or take time off. And if experts are to be believed, it is certainly not the last.
Stress has become a modern-day plague that can lead to a string of complications such as heart problems and even cancer. Steve Tappin, an executive coach and co-author of Secrets of the CEOs, has spent many hours talking to business leaders, both for his book and as part of his work.
"Really these jobs should come with a government health warning," he said. "A friend of mine did a study that found extremely high levels of cortisol [a steroid hormone produced by the adrenal glands] in chief executives, which can lead to accelerated ageing, increased risk of heart attack and cancer."
Mr Tappin, who is in China researching a book on the new generation of Chinese business leaders, added: "Many of the CEOs I speak to are on the verge of exhaustion. The problem that Western chief executives face at the moment is that they are being asked to deliver results ahead of expectations at a time when the economic backdrop is one of low, or zero, growth."
Cary Cooper, professor of organisational psychology and health at Lancaster University, described the job of a chief executive as "horrendous", not only because of the demands placed on them but because the public perceives them in such a poor light.
"These people really do care what people think of them and what they do. Perception is a big issue. Senior people in banks don't like what is going on. Instead of saying they work in a bank, they'll often say they work in the financial sector," he said.
"Integrating businesses is hard work, particularly if you are coming in from outside. You will often have to downsize, and firing people is hard. There is pressure from the Government, pressure from your shareholders, pressure from the regulator and public pressure because people watch everything a CEO does. Details of your salary, and even your holidays and your personal life, will be printed and become public."
Mr Cooper concedes that businessmen are themselves partly to blame for this because they earn so much compared with most people. This point was underlined last week when Income Data Services released a report showing that the salary and bonus package of the average executive director of a FTSE 100 company had increased by 49 per cent in the last year. Chief executives had to put up with a 43 per cent rise – but this is still huge compared with the pay freezes or below-inflation pay increases elsewhere in the public and private sectors.
Mr Cooper said: "Perhaps they could say, 'Well I'm earning £2m, I'll take a 10 per cent pay cut and take £1.8m. That's surely enough to live on'." That sort of thing rarely happens.
Many political leaders, too, have been finding the stress of their job all too much – and their rewards are a drop in the ocean compared with the pay packages of chief executives. Labour's Estelle Morris stepped down as Education Secretary after a bruising period, admitting frankly that she "wasn't up to the job". In Norway, the former Prime Minister Kjell Magne Bondevik took indefinite leave of absence in 1998 as a result of stress-induced depression brought on by the pressures of his job. And in Japan, Shinzo Abe resigned as Prime Minister in September 2007; the next day he was taken to hospital suffering from stress and exhaustion.
Fortunately for Lloyds (and British taxpayers who remain the bank's biggest shareholder) stress is a condition from which it is possible to recover. Ms Morris, for example, returned to the Government, albeit in a different role. And Mr Bondevik was re-elected to a second term after taking a break.
Amy Whitelock, senior policy and campaigns officer at the mental health charity Mind, said there was no evidence that those at the top of organisations are more likely to suffer from stress than junior members of staff. But she added: "What we have found is that the higher up you are in an organisation, the harder it is to talk about or disclose mental health problems. People fear it will have a negative impact on their careers and they will suffer prejudice as a result. We found that one in five employees felt that if they disclosed stress it would put them first in line for redundancy, for example."
It is true that not everyone succumbs. Mr Horta-Osorio has been described by people close to him as a particularly intense and driven character, one who so immersed himself in his new job that what happened was inevitable. Others are better able to manage stress, and even thrive on it. Barclays' chief executive, Bob Diamond, has been on the bank's executive committee for 14 years having previously held senior roles at Morgan Stanley and Credit Suisse, both banking giants.
While he could hardly be described as even-tempered (he has been known to berate reporters at results press conferences if he dislikes their questions) he seems to relish pressure despite taking flak from all corners in recent months. "I wake up each morning with a smile on my face," he once said. "Because my job is about helping people."
Mr Diamond doesn't seem the type to step down because of stress, and there are numerous politicians who seem immune to the condition. An obvious example is Silvio Berlusconi. Despite pressure from the markets and his fellow leaders over Italy's economic woes, the Prime Minister is rarely seen without his Cheshire Cat grin.
Mr Tappin said that one of the biggest problems affecting people at the top of organisations, particularly senior businessmen, was "a difficulty with trusting people". The same is also true of politics. This makes it hard to delegate and to work effectively with others, Mr Tappin added.
"In the future what is really needed is a new, more collaborative model, where you have five or six people at the top who trust each other, people who can come together and agree their dreams and goals for a business and who can work together to achieve that," he said.
Without this, he concluded: "You are going to find this sort of thing happening more often. Much more often."
Steven Cranshaw Former chief executive of Bradford & Bingley
Described as down-to-earth, he resigned in 2008, citing a heart condition at just 47 years of age. Could stress have played a role?
Antonio Horta-Osorio Chief executive, Lloyds Banking Group
The bank was thrown into turmoil yesterday after he took temporary sick leave because of stress and exhaustion.
Kjell Magne Bondevik Prime Minister of Norway
He took indefinite leave in 1998, citing stress-induced depression, but later returned to office and even got re-elected.
Estelle Morris Education Secretary under Tony Blair
Served from June 2001 to October 2002. Effectively admitted she was not up to the job. Returned in 2003 as a junior arts minister.
Joseph Lombardi Chief financial officer, Barnes & Noble
The 49-year-old abruptly quit the struggling US bookstore chain a couple of weeks ago, reportedly as a result of "exhaustion".
Andy Hornby Former CEO of HBOS, then Boots
He resigned this year to take a break after what he said was "an intense five years as CEO of two major companies".
Michael O'Neill Would-be CEO, Barclays Bank
The former US marine was found to have a heart condition, and never took up the job he was offered in 1999. He retired at 53.
Jeff Kindler Chief executive, Pfizer
After four-and-a-half years as boss of world's largest drugs research company, he unexpectedly left last year, saying the demanding role had worn him out.