Sleep deprivation is fuelling the loneliness epidemic because overly-tired people are less sociable, a new study suggests.

Researchers at the University of California, Berkeley, have found that sleep-deprived people feel lonelier and less inclined to engage with others, avoiding close contact in much the same way as people with social anxiety.

The study also showed tired people can pass on their feelings of social isolation to others, almost as if loneliness itself is contagious.

“We humans are a social species. Yet sleep deprivation can turn us into social lepers," said study senior author Matthew Walker, Professor of Psychology and Neuroscience, at UC Berkeley.

“The less sleep you get, the less you want to socially interact. In turn, other people perceive you as more socially repulsive, further increasing the grave social-isolation impact of sleep loss.

“That vicious cycle may be a significant contributing factor to the public health crisis that is loneliness.”