Loneliness can trigger a vicious cycle by making people more selfish which in turn leads to further social isolation, say scientists.
The findings show that such effects create a positive feedback loop between the two traits.
As increased loneliness heightens self-centredness, the latter then contributes further to enhanced loneliness.
"If you get more self-centred, you run the risk of staying locked in to feeling socially isolated," said John Cacioppo, professor at the University of Chicago in the US.
"Targeting self-centredness as part of an intervention to lessen loneliness may help break a positive feedback loop that maintains or worsens loneliness over time," researchers said.
The outcome that loneliness increases self-centredness was expected, but the data showing that self-centredness also affected loneliness was a surprise, said Stephanie Cacioppo, assistant professor at University of Chicago.
In previous research, scientists had reviewed rates of loneliness in young to older adults across the globe.
Five to 10 per cent of this population complained of feeling lonely constantly, frequently or all the time. Another 30 to 40 per cent complained of feeling lonely constantly.
The new findings, published their findings in Personality and Social Psychology Bulletin, are based on 11 years of data taken from 229 individuals who ranged from 50 to 68 years of age at the start of the study.
They were a diverse sample of randomly selected individuals drawn from the general population who varied in age, gender, ethnicity and socioeconomic status.
Early psychological research treated loneliness as an anomalous or temporary feeling of distress that had no redeeming value or adaptive purpose.
In 2006, researchers proposed an evolutionary theory of loneliness based on a neuroscientific or biological approach.
In this view, evolution has shaped the brain to incline humans toward certain emotions, thoughts and behaviour.
"A variety of biological mechanisms have evolved that capitalise on aversive signals to motivate us to act in ways that are essential for our reproduction or survival," researchers said.
From that perspective, loneliness serves as the psychological counterpart of physical pain.
"Physical pain is an aversive signal that alerts us of potential tissue damage and motivates us to take care of our physical body," researchers said.
Loneliness, meanwhile, is part of a warning system that motivates people to repair or replace their deficient social relationships.
"Humans evolved to become such a powerful species, in large part due to mutual aid and protection and the changes in the brain that proved adaptive in social interactions," John Cacioppo said.
"When we don't have mutual aid and protection, we are more likely to become focused on our own interests and welfare. That is, we become more self-centred," he said.