Without doubt the worst moment of Philip Burguieres’s professional existence so far took place in the back of his chauffeur-driven car on the way to the air-port on July 30, 1996. As reading material he’d brought along with him The Wall Street Journal and The Houston Chronicle, and the all-time low hit him when he turned to the business sections.

“I was on the front of both,” he remembers grimly. Burguieres was big news that day for two reasons: because he’d abruptly taken leave of absence from Weatherford, one of the biggest oilfield services companies in the United States. And because stocks at Weatherford had subsequently nosedived by 10 per cent. The two facts were connected because at the time of his departure Burguieres was chief executive. “It was the end of my life as I knew it,” he says. “From a business standpoint, it was, ‘This guy has failed’.”

If you look back at the business press around that time you’ll find out that Burguieres left for nonspecified “health reasons”. The more detailed reports of his departure go so far as to say that the health reasons were “stress-related” and refer pointedly to the time, six years previously, when Burguieres briefly disappeared off the radar in similar circumstances after he resigned as chief executive of the pipeline giant Panhandle Eastern Corp after only 11 months in the job.

The truth, in 1996, was that for several months the 53-year-old $900,000-a-year chief executive had been planning his own suicide. By July 30, he’d whittled down his choices to three options: launch himself off a bridge; shoot himself in the head; or jump from his office window, which looked out on to the suburbs of Houston from the 22nd floor of a skyscraper.

At the time of the car journey described at the beginning of this article, Burguieres was on the way to the $1,000-a-night Menninger, an elite psychiatric clinic in Kansas, leaving behind his staff of 6,246. For Bruguieres it was “the end of my world as I knew it. I was looking at the article and thinking ‘Everybody in the world is going to read this’. I had the responsibility of being chairman, president and CEO. I was a person who never failed at anything. It was the greatest Catch 22 in the world. I couldn’t function and on the other hand I couldn’t let go. I couldn’t think of a way out. So I started thinking illogical things like ‘If I wasn’t here any more’ . . . I didn’t know it at the time, but I was clinically depressed.”

I meet Burguieres not in a skyscraper in Houston but at the Villa D’Este, an ornate lakeside luxury hotel on the banks of Lake Como, where he and his second wife, Alice, are at the tail end of a tour of Europe. Burguieres, at 63, is an approachable and serious man who speaks with a muted Louisiana drawl.

He has agreed to speak to The Times today as part of his campaign to destigmatise depression in the workplace. Since 1996 he has made a full recovery, he says, although “the fear of a return is always in the subconscious.” In career terms he is not, as some would suspect, a broken man. Chairman and chief executive of EMC Holdings, LLC, an investment management company; vice-chairman of the Houston Texans; and chairman emeritus of Weatherford International, he has recently been elected to the board of directors of FMC Technologies, a global provider of technology solutions for industrial markets.

Since going public about his depression in 1997, Burguieres also runs a sideline in counselling other CEOs around the world, “a secret network of CEOs with depression”. “I can’t tell you the number of CEOs who open up to me with their own stories,” Burguieres says. “It would shock you to know how many individuals running major corporations are grappling with suicidal depression.”

Throughout his 40-year career Burguieres appeared in countless business articles and it is striking how much, almost three decades on, he still resembles his 35-year-old self as pictured in the June 1980 issue of the executive’s bible, Business-week. The photograph is accompanied by some text that explains that the bespectacled man you see in front of you has just become the youngest CEO of a Fortune 500 company.

He’d been picked by Cameron Iron Works, a company big in the oil drilling business, without even applying for the job and was earning a salary of $500,000. He should have been thrilled. But the smile in the photograph is, as now, glassy and stiff. How did he feel at the time? “When it was announced in the local paper, I felt let down,” he says. “It wasn’t a high for me, emotionally. I’ve read books about people who climb Everest and feel the same thing when they get to the top. The fun was planning the trip. I didn’t feel good about it and that was a signal: here’s one of the greatest moments of my life and I felt nothing. It was a precursor of what was to come.”

What was to come took another 11 years to happen, and began in earnest the day his secretary heard a thump in her boss’s office. Burguieres had passed out on his desk. Having turned around Cameron, Burguieres had been poached by Panhandle, where he was put in charge of 15,000 staff. Almost immediately, he felt overwhelmed and became an insomniac but put his anxiety down to stress. In hospital, doctors could find nothing wrong. As a last resort they suggested a psychologist.

What followed is either the story of a man in over his head at the top, or the story of a person coming to terms with a mental illness he never knew he had – depending on your point of view. Burguieres insists that what he experienced was the culmination of an undiagnosed depression, not the vertiginous symptoms of a man constitutionally incapable of dealing with the demands of a high-pressure business environment. After Burguieres left Panhandle “a psychologist diagnosed situational depression and that was what I wanted to hear”, he says. “I could blame it on the job so I left and immediately started feeling better.” Barely three months later he was appointed CEO of Weatherford and, within five years, transformed the company from a $100 million business to a $3 billion business.

But then “we were growing the company very rapidly and I got it into my head that one or two of the acquisitions I’d made were not going to work out and I started obsessing about it.” It was around about this time that his first wife’s terminal cancer was diagnosed, and one can imagine that this might have taken its own toll on Burguieres. The insomnia returned and, unable to function normally, he would drag himself out of bed every morning and shut himself up in his office, making a show of forensically studying the business pages, hoping his secretary wouldn’t notice. Phone calls were left unreturned and meetings were delayed indefinitely.

Eight to ten weeks later, “I was scared to death. My thinking became more specific. I really wanted out.” Eventually Burguieres presented his board of directors with a sick note from his doctor stating that he was suffering “some sort of chemical imbalance in the brain that they needed six months to cure”. He checked himself into a mental health clinic for three months, tried seven kinds of antidepressants, but returned home broken, afraid and barely able to function. He slept half the day and was physically exhausted – it took him six months to build up the energy simply to walk around his block. He was convinced that he would never do anything of any significance again. It took two gruelling years “to flip my brain around – the way I view the world now versus the way I viewed it before. I view the world and living life about relationships, helping people, about having meaning in your life.”

It is somewhat astonishing to find out that his wife at the time never suspected that her husband was clinically depressed. “She thought I was stressed because of work and that it would pass eventually.” This analysis seems to be accurate in so far as, the first time round, Burguieres seems to have recovered the moment the pressure was off. When, in 1996, he succumbed again, he did so during a period of high stress at work. Isn’t there an inconsistency in claiming to be in the long-term grip of clinical depression that only shows its head during highly stressful periods in one’s career? He says now that had he not been so fixated on material possessions, achievement or self-gratification in the past “I probably could still be a CEO,” but then goes on to say that he won’t take on another CEO position because “for me, there’s too much risk”. Isn’t that the equivalent of admitting he is not mentally robust enough for the job?

“I was under much more severe pressure serving in the military during Vietnam, running a company in the 1980s and cutting 10,000 employees, having a wife with terminal cancer,” he says. “The illness can be thought of only in the context of every other illness. Lots of CEOs eat right, exercise, and still have heart attacks. Is this because they are weaklings? Depression can hit you from out of nowhere.”

Burguieres eventually emerged from that second depressive episode, not because of drugs or therapy but by going public. By chance he bumped into the high-achieving Texan property magnate John Sage, who confided that he too had been struck down by the black dog. There is something darkly comic about imagining these two hugely rich and successful business pin-ups joking about their suicidal fantasies in an office, but this is what happened. Burguieres became more open about his depression and, in 1997, was persuaded by a friend to talk to 75 CEOs and their spouses about his experience at an event in Houston in 1997. More talks followed. He was invited to give his lecture, Clinical Depression and The CEO, at a conference organised by The World Presidents Association, a group of 3,300 current and former CEOs, during which he read from his own diary. A couple of days later the phone began to ring.

Burguieres’s story would be less pertinent if it didn’t also apply to, he estimates, “25 per cent of CEOs at some point in their lives,” many of whom now turn to him for advice. Burguieres receives calls every day, and twice a week on average he meets other CEOs who have called him in desperation.

“Depression is chronic and widespread in the executive office,” he claims, because the pressure and isolation, as well as the CEOs’ own unique drive to succeed, make those at the top particularly prone: “My own father was a good father and a good person but he found it difficult to achieve what we define as success in life. I didn’t want to be like my father, who had lost his job when I was a child, stayed at home and struggled to fill his days.

“I reacted the other way but I paid for it. I became a workaholic: if I took an afternoon off to play golf ten years ago, I didn’t feel good. I really wanted to be at the office. There was some guilt associated with pleasure. As a CEO, every quarter you get an enormous report card: your earnings release. The pressure is relentless to perform on a quarterly basis rather than over three or four years.”

For the times when there is no possibility of a face-to-face meeting Burguieres has compiled a CEO’s guide to depression. Its 46 pages examine the merits and drawbacks of various treatments and encourage greater openness about the disease: “Every time I read in the newspaper that somebody has left a corporation for ‘health reasons’ I know exactly what it is: it’s depression. You wouldn’t blame a diabetic for being sick, so why do it to a depressive?”

For British readers, one of the most interesting things Burguieres has to say is about his four years working in Britain in the 1990s. “Depression is stigmatised in the US but, if anything, it is stigmatised more in the UK,” he argues. “It’s seen as a weakness and it is difficult, if not impossible, to confront your boss or to be taken seriously on this issue. Depression is also more hidden in the UK, which can be a good thing. Eccentricity in Britain is much more accepted in the workplace, although it is a psychological flaw and, in many cases, a way of coping.” He talks fondly of a senior British executive “I used to have working for me who brought his dog to work every day. I mean, every day. In the US you’d be considered a nutcase”.

When Burguieres turned to his board at Weatherford, it was sympathetic. He remained chairman throughout his absence. Less esteemed or powerful people might have lost their jobs. When we asked the Institute of Directors how most companies view depression within their ranks, Geraint Day, the IOD’s spokesman, admitted that most top-level executives “think depression is an indication that the person can’t cope in that professional capacity”.

Finding work after a depressive illness might be problematic, “because people would assume that it had adversely affected your self-esteem, which it probably would have done. I’ve never heard of a CEO or top-level manager in Britain taking leave of absence for depression. It wouldn’t surprise me if directors took leave of absence describing their illness as something different, because mental illness is still very difficult to talk about. People in the business world don’t always understand it as they do a physical condition because they aren’t sure when or if it will heal.”

Burguieres counters that this sort of view is shortsighted and misinformed and hopes that by outing himself as a depressive, he will encourage big businesses to take a longer-term view of the illness. “Some of the most creative people in the world suffer from depression or other mental problems,” he says. “You need to nurture those people and take care of them because they will be the ones who are going to be valuable.”