Facebook is a "stressful environment" that can make its users feel envious of their online friends' lives and potentially damage their mental health, a new study has claimed, Digital Spy said.

In 'Envy on Facebook: A Hidden Threat to Users' Life Satisfaction?', the German researchers say that over-exposure to social information on Social Networking Sites (SNSs), such as Facebook, can fuel "envy feelings" that "can cause significant damage to users' well-being and impact their life satisfaction".

The researchers, from Humboldt University (Berlin) and Technical University (Darmstadt), surveyed 584 Facebook users on how they felt while using the social network.

More than two thirds of respondents reported having negative feelings while using social networks, with envy of their "Facebook friends" cited as the major reason.

It was found that being confronted with glowing images and status updates of Facebook friends enjoying their lives can fuel "an unpleasant and often painful blend of feelings… caused by a comparison with a person or group of persons who possess something we desire".

The academics said that such feelings can cause significant damage to a user's well-being and also impact on their life satisfaction. Previous research has suggested that it could lead to frustration, mental suffering and even depression.

Passive users, those who do not actively post on Facebook but instead use the site to read their friends' posts, check news feeds or browse photos, were found to be "particularly subject to these painful experiences".

The study found that Facebook users in their early 30s were most likely to feel envious of their friends on Facebook. Women were more likely to obsess over the physical appearance of others and their social standing, while men tended to boast about their own accomplishments at work and at home.

Indeed, the researchers identified a phenomenon they dub the "envy spiral", involving users becoming envious of other people's lives on Facebook, leading to "self-presentation and narcissism" on their own profiles. This embellishment and exaggeration, in turn, causes jealousy in others.