Gordon Flett, a psychology professor at York University and an author of many of the studies said it was natural for people to want to be perfect in a few things, such as in their jobs.

But he added: 'It's when it generalises to other areas of life like home life, appearance and hobbies, that you begin to see real problems.'

Unlike people given psychiatric labels, however, perfectionists neither battle stigma nor consider themselves to be dysfunctional.

On the contrary, Ms Alice Provost, an employee assistance counsellor at the University of California, Davis, who recently ran group therapy for staff struggling with perfectionist impulses, said: 'They're very proud of it. And the culture highly values and reinforces their attitudes.'

Consider a recent study by psychologists at Curtin University of Technology in Australia, who found that the level of 'all or nothing' thinking predicted how well perfectionists navigated their lives.

The researchers had 252 participants fill out questionnaires rating their level of agreement with 16 statements like 'I think of myself as either in control or out of control' and 'I either get on very well with people or not at all'.

The more strongly people thought in this either-or fashion, the more likely they were to display the kind of extreme perfectionism that can lead to mental health problems.

At some level, they know that it is possible to succeed after falling short. But falling short reeks of mediocrity; for them to say otherwise is to spin the result.

The burden of perfectionist expectations is all too familiar to anyone who has struggled to kick a bad habit.

Break down just once - have one smoke, one single drink - and at best it's a 'slip'. At worst, it's a relapse, and more often, it's a fall off the wagon: failure.

This is why experts have long debated the wisdom of insisting on abstinence as necessary in treating substance abuse.

Most rehab clinics are based on this principle: Either you're clean or you're not; there's no safe level of use. This approach has worked for millions of addicts. But if the studies of perfectionists are any guide, it has undermined the efforts of many others.

Ms Provost said those in her programme at UC Davis often displayed symptoms of obsessive-compulsive disorder - another risk for perfectionists. They cannot bear a messy desk. They found it nearly impossible to leave a job half-done, to finish the next day. Some put in ludicrously long hours redoing tasks, chasing an ideal only they could see.

As an experiment, she had members of the group slack off on purpose, against their every instinct.

'This was mostly in the context of work,' she said, 'and they seem like small things, because what some of them considered failure was what most people would consider no big deal.'

Leave work on time. Don't arrive early. Take all the breaks allowed. Leave the desk a mess. Allow yourself a set number of tries to finish a job; then turn in what you have.

'And then ask: Did you get punished? Did the university continue to function? Are you happier?' she said. 'They were surprised that yes, everything continued to function, and the things they were so worried about weren't that crucial.'

The British have a saying that encourages people to show their skills while mocking the universal fear of failure: Do your worst.

If you can't tolerate your worst, at least once in a while, how true to yourself can you be?

IHT