When people who are lonely come down with the common cold, they tend to report severer cold symptoms — more sneezing, more coughing and more painful sore throats, for example — than those who aren’t as lonely, according to a study published recently in the journal Health Psychology.
Interestingly, the study also found no association between people’s perception of their cold symptoms and the size and diversity of their social networks — a finding that underscores how individuals can be lonely even when they are not socially isolated.
“You can be in a crowded room and feel lonely,” said Angie LeRoy, a PhD student in psychology at the University of Houston, in a released statement. “That perception is what seems to be important when it comes to these cold symptoms.”
The idea that loneliness may be linked to poorer health outcomes is not new. Indeed, previous research has suggested loneliness is associated with serious health problems, including heart disease and early death. For this study, however, LeRoy and her colleagues wanted to see what effect loneliness might have on acute illnesses, such as the common cold.
“Suffering from illness symptoms can affect quality of life, limiting an individual’s ability to fulfill normal social roles and daily activities,” they write.
Evidence suggests that loneliness is widespread in the U.S. In a 2010 survey commissioned by AARP, for example, a third of American adults aged 45 and older — particularly people in their 40s and 50s — reported being lonely.
For the current study, the researchers recruited 213 participants, aged 18 to 55. All were healthy, with no chronic physical illness (such as diabetes or asthma) or history of depression or other psychiatric illness within the previous year.
At the start of the study, the participants filled out questionnaires that included standard assessment tools to measure their perceived loneliness and the size and diversity of their social network. Blood tests were also conducted to make sure they hadn’t recently been ill with a viral infection.
All the participants were then exposed (through nasal drops) to rhinovirus 39, a common cold virus, and immediately quarantined in a hotel for five days. They were given meal service three times per day, but were not allowed to have visitors and had to stay on the floors of the hotel designated for the study — without socializing with each other. (If you’re wondering why someone would volunteer for such an ordeal, each participant received $1,060 for his or her troubles.)
About three-fourths — 159 — of the participants became infected with the virus. During each day of the study, they were asked to rank their symptoms, including sore throat, nasal congestion, runny nose, headache, coughing, sneezing, chills and general malaise, on a five-point scale. Any mucus they produced was also collected and weighed.
The researchers’ analysis of the data revealed that the participants who were lonely were no more likely to get infected with the cold virus than the less lonely participants. The lonely participants did, however, report more severe cold symptoms, even though their mucus production showed they weren’t sicker. These results held even after accounting for such factors as age, gender, education, income, marital status, body weight and the season in which the people participated in the study.
The analysis also found that the reports of more severe symptoms were independent of the size and diversity of the participants’ social networks.
“Put simply, lonelier people feel worse when they are sick than less lonely people,” the researchers write in their paper.
Limitations and implications
As the authors themselves acknowledge, this study doesn’t prove that loneliness causes people to perceive their symptoms as being more miserable. Other factors not measured in the study might explain the results. For example, people who are lonely also tend to report poorer sleep than non-lonely people. Lack of sleep, therefore, may have been what made the symptoms of the lonely cold sufferers’ in this study seem worse.
Also, the loneliness of the study’s participants was tested only once, at the start of the study. Some of those people may not have felt lonely by the time they came down with the cold.
Still, the findings of the current study are not out of line with those of other, related studies.
“Previous research has shown that different psycho-social factors like feeling rejected or feeling left out or not having strong social bonds with other people do make people feel worse physically, mentally and emotionally,” said LeRoy.
The effect can be triggered by other factors as well, LeRoy and her colleagues add.
“Anytime you have an illness, it’s a stressor, and this phenomenon would probably occur,” said Christopher Fagundes, the study’s senior author and a psychologist at Rice University, in the released statement. “A predisposition, whether it’s physical or mental, can be exaggerated by a subsequent stressor. In this case, the subsequent stressor is getting sick, but it could be the loss of a loved one, or getting breast cancer.”
“Doctors should take psychological factors into account at intake on a regular basis,” he added. “It would definitely help them understand the phenomenon when the person comes in sick.”
FMI: The study can be read in full online.