Per the previous post…

Loneliness: Human Nature and the Need for Social Connection (Hardcover)
by John T. Cacioppo (Author), William Patrick (Author)

From Publishers Weekly
Eleanor Rigby might have been in worse shape than the Beatles imagined: not only lonely but angry, depressed and in ill health. University of Chicago research psychologist Cacioppo shows in studies that loneliness can be harmful to our overall well-being. Loneliness, he says, impairs the ability to feel trust and affection, and people who lack emotional intimacy are less able to exercise good judgment in socially ambiguous situations; this makes them more vulnerable to bullying as children and exploitation by unscrupulous salespeople in old age. But Cacioppo and Patrick (editor of the Journal of Life Sciences) want primarily to apply evolutionary psychology to explain how our brains have become hard-wired to have regular contact with others to aid survival. So intense is the need to connect, say the authors, that isolated individuals sometimes form parasocial relations with pets or TV characters. The authors’ advice for dealing with loneliness—psychotherapy, positive thinking, random acts of kindness—are overly general, but this isn’t a self-help book. It does present a solid scientific look at the physical and emotional impact of loneliness.

A Cry Unheard: New Insights into the Medical Consequences of Loneliness (Hardcover)
by James Lynch (Author)
"Thirty years ago, anyone blaming loneliness for physical illness would have been laughed at," the editors of Newsweek observed in a March 1998 cover story…" (more)

Amazon.com Review
We’re a lonely society. Twenty-five percent of American households consist of one person living alone; 50 percent of American marriages end in divorce (affecting more than a million children); 30 percent of American births in 1991 were to unmarried women. These factors are linked to an increased risk of premature death, according to loneliness specialist James J. Lynch, Ph.D., who has spent almost four decades clarifying how loneliness contributes to a marked increased risk of developing premature coronary heart disease. "Mortality rates in the United States for all causes of death, and not just for heart disease, are consistently higher for divorced, single, and widowed individuals of both sexes and all races," writes Lynch in A Cry Unheard: New Insights into the Medical Consequences of Loneliness. An important point in this book is that loneliness in childhood has "a significant impact on the incidence of serious disease and premature death decades later in adulthood." School failure is a major contributor to this problem. Children who fail in school are socially isolated and deficient in the language and communications skills that could help them overcome their isolation. Lynch also explores the links between loneliness and premature death, and describes the biological power of human dialogue–which, he says, is more intimate than sexual intercourse, because dialogue involves the heart, not just the body. This is not a fluffy, feel-good book. There are no quick tips, no instant relief from loneliness, no "do now" lists of activities. This book is for readers willing to delve into the subject of loneliness and health risk. Lynch wants you to understand the magnitude of the problem, which he presents in a style that is both academic (with plenty of statistics and graphs) and accessible. He also wants you to understand the complex solution: contact, companionship, and communication. –Joan Price

From Library Journal
Psychologist Lynch’s The Broken Heart: The Medical Consequences of Loneliness (1977) was the pioneering work that linked mental and emotional states to physical well-being. In A Cry Unheard, he expands on the connection between the stress of loneliness and the state of one’s health. Drawing from his own and others’ research, Lynch contends that loneliness has become a silent epidemic, leading to depression and early death. He points out that parents’ use of language and school failure can result in alienation and antisocial behavior, which sow the seeds of loneliness. And while we may seem more "connected" through technology, Lynch warns that technology-induced loneliness is likely to increase and result in even more medical problems. Loneliness, writes Lynch, is a lethal but avoidable poison. While not a "how-to" book, this is worthy of inclusion in larger consumer health collections.
-Valeria Long, Van Andel Research Inst., Grand Rapids, MI 

A lethal but avoidable poison…   I’ve tried for decades to avoid it and all it got me were friends who think I never tried hard enough.  This is why I don’t think I’m going to make it out of my fifties alive.