Cacioppo and Cacioppo noted that loneliness makes a person irritable, depressed, and self-centred, and is associated with a 26% increase in the risk of premature mortality. In industrialised countries around a third of people are affected by loneliness, with one person in 12 being affected severely. These proportions are continuing to increase with loneliness being considered contagious. Income, education, sex, and ethnicity are not protective against loneliness. The effects of loneliness are not attributable to some peculiarity of the character of a subset of individuals. Instead, they are a result of loneliness affecting ordinary people. Loneliness is often stigmatised, trivialised, or ignored. Regardless, loneliness is emerging as a public health problem. Doctors are encountering loneliness, but most do not have the information needed to deal effectively with it in their patients.
The researchers note that loneliness has become a public health problem that could largely be solved within our lifetime but that doing so would require the full engagement and support of the medical community. This is required as the physical health and mental health of a growing number of afflicted individuals and their families and friends is at stake.