Billy Joel told Melvyn Bragg all you need to know about booze and music this week, but said not a word about ex-wife supermodel Christie Brinkley. Bragg's South Bank Show screened that old Uptown Girl video with his-and-hers padded shoulders, where she looked great while Billy looked, well, lucky in a 1980s way.

Tittle-tattle around Brinkley's high-profile divorce from fourth husband Peter Cook hours earlier included the news that Billy still played piano at her house each Christmas, with their daughter Alexa, 20, leading the singalong. In June, Alexa sang with Billy at a charity concert cheered on by Christie and sons. Billy supported Christie all the way.

She needed it. "The man I was living with, I just didn't know who he was," Christie explained to a Long Island judge hearing her divorce from Cook. Twelve years together and she didn't know her husband?

It was a dirty, messy case, open to press and public at Brinkley's request and widely dissected online and in print. His behaviour was appalling, weird in an anxiety-making way. But family courts hear just as bad on an almost daily basis. So why did she go public -- was she crazy exposing her kids to their father's sordid personal life?

The reason might be vindictive but it could also be for Christie's spiritual and emotional survival. Cook, according to a forensic psychologist, is a narcissist who " ... needs constant reassurance that he is a terrific guy, handsome, accomplished, etc." His behaviour seemed to fit the mould -- egocentric, grandiose, deceitful, controlling, predatory, no remorse or empathy for others (excepting himself) and superficially rather charming. She was a prize, an object to be acquired rather than cherished, then rubbished when she got too close. Narcissism is a zeitgeist term, though never one-size-fits-all. It leaped out of clinical handbooks and into business discourse when people started asking why various CEOs and other leaders functioned without thought for the human consequences just as the sub-prime and global credit markets crashed.

After all, they brought it about, didn't they? Trouble is the culture rewarded them with high salaries and bonuses, assuming they knew what they were doing and respected regulations. In which case, you might say it's the age of narcissism, where me-me-me gets noticed faster than I-Thou or one-of-us. Dealing with narcissists should carry a health warning, but with an estimated one in five people fitting the term partly or fully, it's hard to recognise and almost impossible to resist or rise above.

Let's leave Cook out because there's no evidence other than divorce court reports and anyway the term is much misused.

Simply put, narcissists inflict emotional abuse of the most insidious type, as found in workplace bullying, scapegoating and other practices that can and do drive healthy people crazy. Dr Marie Therese Hirigoyen named it a 'stalking the soul' before she campaigned successfully to have emotional abuse outlawed in French workplaces. She argued that malignant or toxic narcissists are perverts who are attracted to the human qualities they lack -- joy, vitality, caringness, enthusiasm. Think of Rachel O'Reilly.

Non-narcissists can't understand that narcissists mirror normal human behaviour without feeling it so can't cope with the mind games or destabilising tactics. They're actors with nothing underneath. Once involved with the object of their attention -- seducing them with utmost care -- narcissists undermine partners, friends or colleagues until their life-affirming qualities are quashed and their sense of self is in shreds.

They're aggressive, argumentative and provoke rows all round them, usually covering their tracks under a nice demeanour. They accuse others of their own shortcomings and capitalise on normal self-doubt. Often, they enlist supporters who do their dirty work, not realising how strings are being pulled.

This emotional torture is devastating in love relationships and can carry lifelong effects if you're born to a narcissistic parent, male or female. Blogs show extraordinarily similar testimonies from people all over the world. Bloggers speak of constantly upping their game to appease a toxic narcissist, who will never be satisfied, of losing faith in themselves because the narcissist deliberately misunderstands, refuses to listen or acknowledge they're distinct.

The most extreme are high-functioning psychopaths who bend laws without breaking them. Dr Robert Hare psychologised them in the US. "A good psychopath can play a concerto on anyone's heart strings," he advises. "Like the rest of us, most psychopathic con artists and 'love-thieves' initially hide their dark side by putting their best foot forward.

"Cracks may soon begin to appear in the mask they wear, but once trapped in their web, it will be difficult to escape financially and emotionally unscathed.

'Know what you are dealing with," he says. "This sounds easy but in fact can be very difficult. All the reading in the world cannot immunise you from the devastating effects of psychopaths. Everyone, including the experts, can be taken in, conned, and left bewildered by them."

Best advice for people involved with a narcissist is to challenge the image and get away fast as you can or you'll be an emotional wreck. This might be why Christie let reporters in -- and paid Cook off. He cost her $2.1million, as well as the heartache. She probably reckons it was cheap at the price.

mruane@independent.ie

- Medb Ruane