Loneliness is a common experience in human life. It may arise from the ordinary vicissitudes of living. Loneliness, on occasion, confronts all individuals in all walks of life and at all stages of life. It is a quite normal and natural phenomenon.
However, a condition of chronic loneliness has been shown to have more serious implications. John Cacioppo, a social psychologist from the University of Chicago, has been engaged in protracted studies regarding the biological effects of a chronic state of aloneness. As a result of his numerous investigations, he, with the help of his collaborators, has discovered changes that occur in the cardiovascular, immune and nervous systems in chronically lonely individuals. In fact, it has been well established that individuals suffering loneliness have increased mortality.
Cacioppo has been involved in the study of the human brain's role in social behavior and is, in fact, credited with being a founder of the discipline of social neuroscience. As a result of his extensive studies into loneliness, he has come up with some very important findings.
It is the perception of loneliness that seems to be more important than the number of social contacts a person may have. This perception has definitive physiological impacts that adversely affect health. It seems that lonely people have an activated sympathetic nervous system; this system is involved with the flight or fight response. The neuro-transmitters that are produced as a result of this response, epinephrine and cortisol, lead to the constricting of blood vessels that increase blood pressure and put added stress on the heart. In addition, the subjective feeling of loneliness impacts the immune system, resulting in an increase in the inflammatory response – implicated in heart disease – and a decrease in the capability of the body to fight viral infections. It has also been reported that the area of the brain, the ventral striatum, implicated in the brain's reward circuitry has been shown to have decreased activity in lonely people as compared to "normal" controls. Some genetic susceptibility to this state of mind has also been shown.
These data strongly suggest that loneliness has an adverse impact on the quality of life and the general health of those who suffer from it. It is somewhat troubling that modern life seems to make individuals even lonelier. The current estimate – as compiled by the U.S. Census Bureau - is that 29% of the population lives alone; this represents a 30% increase from 1980.