A study from the University of Chicago found that those who felt lonely were significantly more likely to suffer from fragmented sleep.
The researchers compared the degree of loneliness reported by 95 adults in rural South Dakota, USA. Although none of the individuals were socially isolated, their perceptions of loneliness varied - and those who felt more lonely had more difficulties with sleep.
These findings are similar to an older study from 2002 that looked at loneliness in students. That study found that the lonelier the students felt, the more fragmented their sleep.
Further evidence that insomnia and other sleep disorders can often be linked to social and psychological issues.
Oh, and before thinking all you need to do is attend more social gatherings to cure your insomnia, it's worth mentioning that loneliness and social isolation are two separate entities - it's perfectly possible to be surrounded by close friends on a daily basis but still feel lonely.
If you think feelings of loneliness are affecting your sleep, speak with your doctor.
Source: SLEEP Journal