We've all probably known at least one narcissist, whether they were diagnosed as one or not. At its more extreme, disordered end, people diagnosed with Narcissistic Personality Disorder (NPD) display an excessive interest or admiration for themselves, a sense of entitlement and a lack of empathy.

It's estimated as much as five percent of the population, mostly males, have actual NPD, but narcissism comes in a range of shades, many falling below the threshold of a clinical diagnosis.

People with higher levels of narcissism are more sensitive to feeling excluded, leading them to frequently perceive they are being left out or ostracized.

Narcissists are generally not easy people to be around. They demand a lot of attention. As it turns out, however, it can also feel uncomfortable to be someone who fits this description. Because they think they deserve so much attention, narcissists are sensitive to slights and this means they have a tendency to feel ignored or ostracized — and that in turn fuels their aggressive behaviors.

“Feeling ostracized is a subjective experience based on the perception of social cues by the individual. Some may be intentionally ostracized, while others may merely believe they are being excluded when that's not the case,” the study's lead author, Christiane Büttner of the University of Basel, explained in a press release. “Our findings suggest that individuals with higher levels of narcissism are more sensitive to exclusion cues, leading them to perceive ostracism more frequently.”

The researchers came to this conclusion after first analyzing data from the German Socio-Economic Panel, a long-term national survey of approximately 22,000 households in Germany. The team concentrated on nearly 1600 participants whose responses to questions about narcissism and ostracism revealed that they had experienced notably more ostracism in their lives.

The Swiss researchers contacted 323 of these individuals and conducted a two-week study. During this period, the participants completed narcissism assessments, as well as reporting their past feelings of ostracism. Using a mobile app during the following 14 days, they noted the times when they felt excluded or neglected.

“Participants with higher narcissism scores reported feeling excluded more frequently in daily life, aligning with our earlier survey results,” Büttner said.

The researchers then conducted a series of experiments that involved more than 2,500 participants to follow further the connection between narcissism and feelings of exclusion. For instance, in one experiment the individuals joined a virtual ball-tossing game where two players either included or excluded them. The participants were then asked to assess how excluded they felt.

Once again, the results showed that narcissistic people were more likely to see those situations that were ambiguous, when ostracism wasn't really clearly indicated, as exclusionary. But experiments revealed that folks really do prefer to avoid those individuals who are highly narcissistic.

Narcissists are not easy people to be around. They demand a lot of attention.

“Narcissism may contribute to social exclusion, but ostracism itself can also fuel the development of narcissistic traits,” Büttner explained. In other words, it's a two-way street.

They came to this conclusion after analyzing 14 years of statistics from a national survey in New Zealand that involved over 72,000 participants. The researchers observed that among those surveyed changes in feelings of exclusion were followed by an increase in narcissism levels a year later — and vice versa.

These findings suggest that developing interventions focused on helping narcissists learn how to improve their social interactions and reduce interpersonal friction could help both narcissists and those who are in relationships with them.

The study is published in Journal of Personality and Social Psychology.