Using Facebook is like staring at yourself in an online mirror. Those who spend hours updating their profile on the site are more likely to be narcissists or suffer from low self-esteem, said researchers.

They tend to use the site for promoting themselves to friends or people they would like to meet, reports the Daily Mail.

Facebook provides an ideal setting for narcissists to monitor their looks, permitting them to thrive on 'shallow' relationships while shunning genuine warmth and empathy, the study said.

Researcher Soraya Mehdizadeh from York University in Canada asked 100 students, 50 males and 50 females, aged between 18 and 25 years, about their Facebook habits, according to the journal Cyberpsychology, Behaviour And Social Networking.

They all took psychology tests to measure their levels of narcissism, which the study defined as 'a pervasive pattern of grandiosity, need for admiration, and an exaggerated sense of self-importance.'

Those who scored higher on the narcissism test checked their Facebook pages more often each day than those who did not.

There was also a difference between men and women - men generally promoted themselves by written posts on their Facebook page while women tended to carefully select the pictures in their profile.