Be careful, your Facebook page reveals more about you than you might imagine, research finds.



How many friends you have, how many messages you post and how many photos you tag of yourself on Facebook have been directly linked to how narcissistic you are.



Hundreds of thousands of New Zealanders use Facebook every day - but while some are careful about what they share, and who they share it with, others post intimate details about themselves, numerous photos and will become Facebook friends with people they don't even know.



Narcissism is an excessive love or admiration of one's self.



While social media sceptics have long believed that there are links between Facebook and narcissism, a new study, published in the journal Personality and Individual Differences, now confirms it.



Researchers at Western Illinois University studied the Facebook habits of 294 students, aged between 18 and 65, and tested two "socially disruptive" elements of narcissism, The Guardian reported.



They discovered that people who scored highly had a very active Facebook presence, regularly updated their newsfeeds, posted photos of themselves and had a lot of Facebook friends.



They often changed their profile picture and would respond more aggressively to negative comments made about them on the site.



Victoria University acting head of psychology Marc Wilson said narcissists tended to use Facebook as an outlet.



"Facebook is a great way for people who think they're particularly flash to index how flash they think they are," Wilson said.



Narcissists were likely to add more friends than others "but they're not friendships, they're not even acquaintances.



"Narcissists might be particularly careful about who they friend. They might only friend people who they think are physically attractive as that reflects better on them."



The socially disruptive elements that were measured were grandiose exhibitionism which includes self absorption, vanity and exhibitionistic tendencies, and entitlement/exploitativeness, which the researchers described as "a sense of deserving respect and a willingness to manipulate and take advantage of others".



The higher someone scored on the grandiose exhibitionism scale, the more Facebook friends they were likely to have.



The research stated that they crave attention and were likely to make inappropriate comments because they couldn't stand to be ignored or waste an opportunity to self-promote.



Those who rated highly on both scales were also more likely to seek support from their social network, but less likely to offer it.



Research from the United States has shown that young people are more narcissistic these days than they were 20 years ago, Wilson said.



Research the psychology professor had conducted himself in New Zealand showed that teenagers and those in their early 20s were more narcissistic than people older or younger than them.



"We live in a society these days where people are told to believe in themselves and that they're special."



Whereas in the 1950s children were taught that the most important thing was to be obedient, they were now being taught "to believe in themselves", Wilson said.



"There are clearly lots of pluses to this but there is a downside to telling people that they're the best thing since slice bread."