In fact, Dr Hart believes that people who can identify certain narcissistic traits in their own personalities are reasonably healthy individuals.
"A lack of insight is one of the characteristics of narcissism," she says.
"So it's a good sign if you can identify some of these qualities in yourself because it means you're relatively healthy psychologically."
Uncovering a narcissist
These days, the term "narcissist" is often used to describe a vain or selfish person who is particularly self-absorbed. But this common perception of narcissism is overly simplistic and doesn't reflect the true complexity or potential severity of the condition, Dr Hart says.
"Often when people think of narcissists, they see them as these people who put a huge amount of attention just on their looks," she says.
"There are other, quieter, kinds of narcissism as well ... the narcissist may even be quite shy but what's going on in their head is them believing they're naturally superior to everyone else."
Dr Hart describes some of the more common characteristics of narcissism:
• Feels superior
The most obvious trait of a narcissist is their sense of grandiosity, superiority or even arrogance. There's this belief that as a person they're better than any other human being.
Is self-entitled
Along with that comes a delusional over-sense of entitlement. People who have good psychological health will feel a healthy sense of entitlement, but narcissists just feel they're more entitled than anybody else.
• Lives in a fantasy world
Narcissists live in this fantasy world where they're a wonderful person and they have these images of extraordinary success and power and maybe love as well. They live not in the real world but in this idealised bubble, which results in a warped sense of perception about things.
• Needs to be admired
They also have this intense need to be adored and admired that has to happen all the time. When speaking to a narcissist, it's very difficult to have a reciprocal conversation with them. They won't listen very attentively to you and will somehow always manage to bring the conversation back around to them.
• Will manipulate
Narcissists tend to use or exploit people and will often manipulate a situation in such a way that they get other people to do a lot of their boring or dirty work for them. Somehow or other they manipulate a situation so they come out getting the glory for it.
• Lacks empathy for others
Another very important characteristic is a serious lack of empathy in that they really can't put themselves in the shoes of another person to really feel what it's like. They'll often be quite cold, particularly when others are distressed or going through an emotional upheaval.
• Will never apologise
Narcissists will almost never apologise or admit that they have been wrong. They never really take ownership or responsibility for themselves and their own lives, particularly with regard to other people, and often don't feel the need follow through on their often grandiose promises.
• Hate to be criticised
Another important characteristic is that they've got virtually no tolerance for even the slightest criticism or even constructive advice. Anything that's got even a sniff of criticism, they're highly reactive to.
• Is very changeable
One minute a narcissist may consider you to be the most wonderful person in the world and can't do a thing wrong, and the next they've flipped into completely devaluing you. These rapid and extreme switches of behaviour can be really difficult to manage as someone who is trying to deal with a narcissist.
A narcissist, by degrees
Dr Hart says we all show narcissistic traits from time to time.
"Sure, we can all be self absorbed at times, but everyone expects that sometimes. Or perhaps you're not always that considerate of other people but that's just normal, too," she said.
While narcissism is relatively common, its severity can vary dramatically between individuals. "Narcissism is on a spectrum, which is why it's very hard to talk about incidence of it in society," Dr Hart explains.
"There's a huge level of degrees from one extreme to the other but I would say, probably, up to about 15 per cent of the population have some degree of narcissism in them and that around 75 per cent of those will be male."
At the extreme end of the spectrum, Dr Hart says a narcissist is considered to suffer from a condition called Narcissistic Personality Disorder (NPD).
"About 1 per cent of the population are considered to have this disorder," she says.
"At the disorder end of the spectrum, a narcissist is almost impossible to live with.
"They create enormous difficulty and havoc in everybody's lives."
