Loneliness can make cold symptoms feel worse, study finds

— -- Few Americans will escape a year without the tell-tale sneezing, coughing and general misery that are symptoms of the common cold. However, a study published today in the journal Health Psychology finds that people who are feeling lonely are likely to feel much worse.

"Put simply, lonelier people feel worse when they are sick than less lonely people," the authors wrote.

For this study, researchers looked at data from 159 non-partnered people between the ages of 18 to 55, who were asked questions about how often they felt isolated, left out, or lacked companionship. They were also asked objective questions about the size, quality and diversity of their actual social networks.

The participants, who were paid, were then infected with the RV39 common cold virus through nasal drops and spent the next 5 days quarantined in a hotel, recording the severity of their symptoms each day. They were asked about how much certain moods described their feelings, on a scale of 0 to 4. Researchers assessed how depressed participants might have been on each day of the quarantine by taking a mean score of one "sad" and one "unhappy" item.

They also asked participants to answer specific questions about how they perceived their relationships and whether they felt like they were lonely or isolated, meaning the amount of contact they had with their social contacts in a two week period. Those who had the highest measures of loneliness reported more severe cold symptoms. At the end of the study, blood and nasal secretion samples were taken to ensure that each participant had truly been infected with the virus.

The authors stressed that it was those who perceived themselves to be the loneliest, not necessarily those with the smallest or weakest social networks, who said they had more severe symptoms. How someone feels about their loneliness is often more important than how socially isolated they really are, based on numbers of family and friends alone.

"It is critical for clinicians and researchers to consider the perceived quality of people's social relationships (i.e. the experience of loneliness)," the authors continued, "which may be an even more powerful predictor of acute illness-related symptoms than the quantity of relationships."

But the reverse did not appear to be true: A person's perception of loneliness did not make them more or less likely to develop cold symptoms, according to the study.

"If you’re already feeling a bit isolated socially, you’re more likely to perceive a cold as a downer," Dr. William Schaffner, infectious disease expert at Vanderbilt University Medical Center told ABC News. "Colds generally make you feel less socially interactive: more withdrawn, more inner directed. You want to curl up and go to sleep. So if you’re already feeling lonely, you could be more lonely and depressed and social isolated."

Schaffner said the findings could give people added incentive to take steps to avoid the cold and flu, especially by getting a flu shot.

"It’s not how frequently they got a cold, but once you had a cold, how did you characterize it? How did you feel about it? That’s heart, thinking is brain," Schaffner said. "If you’re already feeling a bit isolated socially, you’re more likely to perceive a cold as a downer."

This is one of several recent studies highlighting the effect a person’s loneliness can have on their experience of an illness. The authors expressed hope that these results encourage doctors and patients to have conversations about social connectedness, to address what may be causing patients the most distress.

The study findings are still preliminary due to the small sample size and because researchers excluded people with chronic illness such as diabetes or asthma, pregnant women, anyone with a psychiatric diagnosis in the past year and anyone who had cold symptoms in the previous 30 days.

Dr. Carolyn Certo Gnerre is a third year psychiatry resident at Montefiore Medical Center in New York and resident in the ABC News Medical Unit.