Answer: When you need someone to defuse a bomb.

That's about it really - for a team. And only because psychopaths don't feel fear the way regular folks do. (Of course non-psychopaths defuse bombs too and it's their triumph over fear that we admire so much.)

Why might you need to know more about psychopaths?

For your protection, but also for reassurance.

About one per cent of the population qualifies as a psychopath. It's higher for some professions.

Let's set aside a couple of myths

All psychopaths are criminals. Some are, but most are law-abiding and productive citizens.

You are either a psychopath, or not. It's a scale and almost everyone is on it. A leading figure in the research describes the symptoms as like a sound mixer. It's only when most of the sliders are ramped up that we see a full-blown psychopath. 

Some of the warning signs

• Superficial charm

• Lack of empathy, callousness

• Grandiose estimation of self

• Impulsivity

• Manipulative behaviour, cunning

• Lack of remorse or guilt

• Lack of fear

• Pathological lying

• Failure to accept responsibility for own actions

• Lack of realistic long-term goals

• Lack of remorse of guilt

If you are going to appoint or promote someone with just one prominent symptom, check for more. Look behind superficial charm. Be wary of grandiose self-confidence. Know what you are getting into.

These days, success in most teams takes high levels of honesty, self-control and concern for others' rights and feelings.

Take care with assessments - even your own

You'll find questionnaires on the internet inviting you to check whether 'you might be a psychopath'. I've seen some that accurately list the 20 characteristics in the Hare Psychopathy Scale developed by a Canadian professor, Robert Hare, and widely used. (My selection comes from the same list.) One is written by another researcher and reflects the same characteristics of psychopaths.

Here's the problem:  Questionnaires are only one of the methods trained clinicians use to form a diagnosis. Anything less is just a guide.

Keep in mind that non-psychopaths and psychopaths share some characteristics. How much of each characteristic is a key issue. A little bit of insensitivity might be useful. How would you cope if you had so much empathy that you were tortured with worry about how each team member might feel about any decision you make?

Jobs for psychopaths

Some roles are more suited to people who are immune to fear and stress - not just bomb-disposal, but spying, motor racing and window cleaning on skyscrapers.

Any role that demands a high degree of professional detachment and tough decisions would be more suited to someone who scores lower on empathy.

Politicians have an advantage if they can convince us that they are sincere, intelligent and supremely confident. It helps if they are charming and witty too. Psychopaths can create those impressions and tell us what we want to hear. It's the way to get elected and get things done. If we agree with their politics and they only have some of the symptoms of a psychopath (think of the sliders) maybe no problem.

Kevin Dutton, a prominent authority on psychopaths from Oxford University, has written a fascinating book 'The Wisdom of Psychopaths'. His research reveals a wide range of other useful attributes of psychopaths including a can-do attitude, assertiveness and a focus on the positive. 

Those qualities are useful, but if we are thinking of recruiting someone to join us, let's be sure that we avoid the sliders that represent cunning, callousness, irresponsibility and other characteristics that even in small doses could destroy the team.