Loneliness is a subjective experience of social isolation and occurs when people feel disconnected from others. One can be surrounded by others but still feel lonely, and conversely, one can be alone, but not feel socially isolated. It refers to a negative perception of one’s relationships. Whilst loneliness can be a distressing feeling, it serves a function as it prompts us not to depend solely on our own resources.
For more than 4 decades, we have known that social networks affect health through a variety of mechanisms, including provision of social support (both perceived and actual), social influence (e.g. norms, social control), social engagement, person-to-person contacts (e.g. pathogen exposure, second-hand cigarette smoke) and access to resources (e.g. money, jobs, information).