Loneliness triggers cellular changes that can cause illness, study shows

http://www.eurekalert.org/pub_releases/2015-11/uoc-ltc112015.php

Public Release: 23-Nov-2015
Loneliness triggers cellular changes that can cause illness, study shows
University of Chicago

Loneliness is more than a feeling: For older adults, perceived social isolation is a major health risk that can increase the risk of premature death by 14 percent.

Researchers have long known the dangers of loneliness, but the cellular mechanisms by which loneliness causes adverse health outcomes have not been well understood. Now a team of researchers, including UChicago psychologist and leading loneliness expert John Cacioppo, has released a study shedding new light on how loneliness triggers physiological responses that can ultimately make us sick.

The paper, which appears Nov. 23 in the Proceedings of the National Academy of Sciences, shows that loneliness leads to fight-or-flight stress signaling, which can ultimately affect the production of white blood cells.

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Finally, the researchers determined that this monocyte-related CTRA shift had real consequences for health. In a monkey model of viral infection, the impaired antiviral gene expression in "lonely like" monkeys allowed simian immunodeficiency virus (the monkey version of HIV) to grow faster in both blood and brain.

Taken together, these findings support a mechanistic model in which loneliness results in fight-or-flight stress signaling, which increases the production of immature monocytes, leading to up-regulation of inflammatory genes and impaired anti-viral responses. The "danger signals" activated in the brain by loneliness ultimately affect the production of white blood cells. The resulting shift in monocyte output may both propagate loneliness and contribute to its associated health risks.