Some individuals are at greater risk than others for feelings of loneliness because of development issues -- for example, shy children who are excluded or rejected by other children, he said.

CNN: Feeling lonely? Genes might be at fault

Her very presence seemed to irk married women of her age, not because they saw her as a threat but, rather, because her widowhood and loneliness reminded them that they could end up like her.

NEWYORKER: Luda and Milena

Before civilisation intervened, such chronic loneliness would have been so rare (because isolated individuals are so vulnerable to predation) that evolution would have ignored it.

ECONOMIST: The reason loneliness could be bad for your health