Most of us can be selfish, self-centered or even ruthless. But these acts are rarely harmful. For some people who suffer from a personality disorder, however, these characteristics can become harmful to themselves or their surroundings. 

- What distinguishes people with a personality disorder is that they have a lot of problems with their relationships with other people. Their way of perceiving and interpreting the world is not entirely based in reality. Experiencing what others say and do is like a laughing mirror, says Jenny Klefbom, a licensed psychologist with extensive experience researching personality disorders.

- Narcissists find it easy to attract people — they are attractive in a way and radiate energy. They are quite preoccupied with thoughts of how great they are and they like to boast. If they are smart, they can boast skillfully; they are charismatic and admirable at first.

It is easy to confuse with psychopaths with narcissists, but they are not the same. Psychopathy is not a standard diagnosis, but people with a serious form of antisocial personality disorder are usually called psychopaths. Psychopaths are characterized mainly by a complete lack of conscience, guilt and compassion. Symptoms and signs may be similar, but it's still a big difference.

- Narcissists are not necessarily deceptive, but it's a bit like a Disney movie, when it comes to whether they're showing their true face, says Jenny Klefbom.

Jeanette Paludan is founder of the company Management Partners and has a book about dealing with other narcissists in love relationships. Paludan has extensive experience in helping organizations manage managers and employees who have narcissistic and manipulative qualities.

A commons characteristic among narcissists is that they find it extremely difficult to accept management and control from the top. They do not tolerate when someone else makes decisions. The scary thing is that it is very difficult to notice this because they are often so very manipulative.

Jeanette Paludan says that narcissistic people often find it difficult to talk about their weaknesses, for example in job interviews and are often very sensitive to criticism.

- A characteristic of narcissists is that they are not happy, even if they have everything; a partner, children and a nice job. They always want more acknowledgment and attention.

How do you recognize a narcissist?:

* Boasts and exaggerates their talents and successes

* Believe themselves to be "special" or better than others, and requires to be treated that way

* Requires a lot of attention, praise and admiration from others

* Values their own needs above others and uses others

* Has difficulty empathizing with the situation of others — "does not care"

* Often perceived first as charismatic and exciting, but changes to become arrogant and condescending when they are on the offense.

Source: Jenny Klefbom, licensed psychologist.

-Hugo Ewald/Ida Gustafsson