Loneliness: Human Nature and the Need for Social Connection
Cacioppo, J. T. (2008). New York: W. W. Norton

John T. Cacioppo's groundbreaking research topples one of the pillars
of modern medicine and psychology: the focus on the individual as the
unit of inquiry. By employing brain scans, monitoring blood pressure,
and analyzing immune function, he demonstrates the overpowering
influence of social context—a factor so strong that it can alter DNA
replication. He defines an unrecognized syndrome—chronic
loneliness—brings it out of the shadow of its cousin depression, and
shows how this subjective sense of social isolation uniquely disrupts
our perceptions, behavior, and physiology, becoming a trap that not
only reinforces isolation but can also lead to early death. He gives
the lie to the Hobbesian view of human nature as a "war of all against
all," and he shows how social cooperation is, in fact, humanity's
defining characteristic. Most important, he shows how we can break the
trap of isolation for our benefit both as individuals and as a society.
Source: Loneliness