The LED on his answerphone read zero when Sam returned to his flat last night following after-work drinks with colleagues. Today he'll sleep in, watch a DVD or two, play Xbox and call his mum. Tomorrow he plans to slip back into the office for a couple of hours.

Sam has few friends outside work and the last two (brief) relationships he had originated in the office. He's carrying over holidays to next year (again) and the five-day Christmas shutdown is, he believes, too long.

But Sam is not like his father, a workaholic who became an alcoholic. Sam believes he is different because he finds meaning in his work. He is an agency "creative" and some of his clients are NGOs and voluntary sector organisations. He loves what he does. He wakes up at 3am buzzing with ideas. His dad hated his job and lay awake worrying about work.

People are taking their work more personally than ever. And it's healthy to find meaning and fulfilment in our work, to be passionate about what we do. But what happens when our work becomes too personal?

Phillip Hodson meets people like Sam - lawyers, bankers, journalists, actors - on an almost daily basis at his north London counselling and psychotherapy practice. "I see a lot of clients who work double-digit days but don't understand why they have started walking in front of buses, why they can't sleep any more, why they have no partners - why they have no life." Many are depressed, says Hodson, but the reason is not some horrible trauma. It's because they love their work too much.

Research by consultancy Penna suggests a quarter of British workers are so passionate about their job they believe it defines who they are and gives their life meaning. For a significant 12%, work is the single biggest provider of "community and belonging". A fifth have built up a close network of friends through their workplace, a figure that rises in London, where the workplace is an even more important social agent. A quarter of directors say they get more meaning from work than at home or socially. Another poll says more than 90% of employees would rather find a new job than love this Christmas.

British workers spend 60% of their waking hours in work, but many put in long hours because they want to, rather than out of economic necessity. The workplace, instead of the home, is where they make friends, feel supported and find opportunities to "make a difference".

Older workers - those in their 40s and 50s - were brought up on a live-to-work ethic: work harder, work longer, earn lots of money. In contrast, surveys suggest younger workers focus on quality, not quantity of work. They take it for granted that they will be paid well. But they want work to mirror their values, too.

Younger workers hope to avoid the mistakes their parents made. But the lure of work that is "significant" or "challenging" can be incredibly seductive. You know who they are - friends for whom work has become their sole passion, their primary source of self-esteem, recognition and respect. Maybe it's you.

Having a job that makes you feel valued and part of a community does not in itself render you unbalanced. The imbalance occurs when work is the only place where your needs are being met.

Workplace shocks such as redundancy, being passed over for promotion or poor appraisals can be devastating - an awful epiphany when you discover that work is not a meritocracy, your boss is not your friend and your colleagues are not your family. In short, bring your heart and soul to work, and there's a good chance you'll end up feeling betrayed.

For people with partners and families, marital or sexual problems are often an early warning sign, says Hodson. "Many of my clients have become so adrenalised by their job that everything else, even playing with their children or looking after their partners, gets lost. Young entrepreneurs tell me that they're 'only doing it for the family'. But it's bollocks. They're doing it for themselves. I find it very strange that you would build a family and then spend most of your time away from it."

Employers, meanwhile, are joining the dots, ready to believe that more engaged workers are more productive workers. "Employees will be more motivated, loyal, creative and productive in an organisation that has helped them find meaning at work," says Gary Browning, chief executive of Penna.

Nokia, Unilever, McKinsey, Shell, Coca-Cola, Hewlett Packard, Merck Pharmaceuticals, Starbucks and the Co-operative Bank are among the big employers exploring the concept of "spiritual intelligence". While emotional intelligence is about what we feel, spiritual intelligence (SI) concerns the soul and the quest for purpose and meaning.

For some employers, the interest is as perfunctory as rewriting mission statements to include "social responsibility" or "the environment". But others are introducing the SI concept into their management processes and business practices.

Danah Zohar, the academic who wrote the book (literally) on spiritual intelligence, defends employers' right to create meaning at work. "The point is not to find all our meaning at work, but to find more meaning at work," she says. "It's not a case of making work more meaningful than home, or vice versa. The more meaning the better, wherever we find it.

"Most executives have to work long hours; that's what is expected of them. But I know many who are now happy to work a 16- or 17-hour-day because they've found meaning."

Should we accept that work is our new religion, where we worship and sacrifice our time? Or should we put our work back in context? The Spanish word for work, "trabajo", comes from a Latin word for an instrument of torture. Even the Puritans considered work a means to an end.

Successful companies are usually the ones that stick to their core competencies. Maybe the smart ones should trust their employees with the time and space to find more meaning outside work, and leave spiritual experiences to babies in mangers.

· Spiritual Intelligence by Danah Zohar and Ian Marshall is published by Bloomsbury at £7.99

Are you taking your work too personally? Is your passion for the job healthy or harmful? Take our quiz to find out

1. On Monday mornings are you:

a) Eager to get back to work

b) Reluctant to start another week of work

c) Neither anxious nor reluctant

2. Do you get to work early to make a head start on things?

a) Often

b) Sometimes

c) Never

3. Do you take work home and work late into the night?

a) Often

b) Sometimes

c) Never

4. Do you ever work while you eat lunch?

a) Often

b) Sometimes

c) Never

5. If you were made redundant, what would you miss the most?

a) The company of your colleagues

b) The work itself

c) The money

6. If you won a large sum of money, would you:

a) Continue in the same line of work as you do now

b) Pursue a different career

c) Quit working altogether

7. The most important thing in your life is:

a) Your career

b) Your friends and family

c) Your weekends and annual leave



8. You feel most fulfilled:

a) When you've just completed an important project at work

b) When you're spending time with friends and family

c) When you're in the pub

9. Do you take all your holiday entitlement?

a) No - and you haven't had a holiday for two years

b) Yes - your mind, body and soul needs the break

c) Of course - plus as many sickies as you can get away with

10. This year's Christmas card list is:

a) Exclusively work-related

b) A mix of friends in and outside the office

c) I don't do Christmas cards

The answers

If you answered mostly b or c, stop reading now (we'll deal with your particular neuroses another day). But if you answered mostly a, it's time to take a scythe to the hours you work. If you constantly give 100% to your job, you'll leave nothing for friendships, family or yourself. Take up a hobby, join a club or enrol on a course. Stop bringing work home and devote at least one hour a day to the main relationship in your life. Build a circle of friends outside of work who are fun to be with. Call up some old friends every week and go visiting at weekends. The Christmas party shouldn't be the social highlight of your year.