Loneliness may hamper the immune system, which is needed to fight off illness.

That's what Carnegie Mellon University psychology graduate student Sarah Pressman, MS, and colleagues found when they studied college freshmen coping with their first semester away from home.

The freshmen who felt the loneliest and most socially isolated had the weakest immune response to one component of the flu virus, says Pressman.

The results -- published in May's Health Psychology -- show that loneliness and social isolation can have an impact and that the first semester of college can be "really stressful," Pressman tells WebMD.

Emotional Feeling, Physical Effect

College students aren't the only ones whose health may suffer with those feelings. "Loneliness and social isolation have previously been associated with immune detriments," says Pressman.

"As you get older, the immune system doesn't work as well," she says, noting that older people's social networks sometimes thin as friends and family move away or die.

A study of 180 senior citizens found an association between loneliness and heart disease. That report appeared in the December 2002 issue of the Annals of Internal Medicine

Campus Study

Pressman's study included 83 first-semester college students. All were healthy and got their first-ever flu shots on campus, along with the rest of their class.

Researchers often use students' response to flu shots as a measure of immunity. "The nice thing is it's a bit more relevant than a blood draw and looking at circulating antibodies," says Pressman.

Two days before the flu shot, the students were given palm-held computers that prompted them to rate how lonely and isolated they were feeling at that moment on a scale of one to four. The computer tests popped up four times each day for about two weeks.

The students also wrote down the initials of all the people they had contact with at least once every two weeks.

Pressman and colleagues grouped the students in two ways: by degree of loneliness (low, medium, or high), and by social-network size (smaller, medium, or larger).

Lonely Students, Weaker Immune Response

Blood samples showed that the loneliest and most isolated students had weaker immune responses to the flu vaccine.

The weakest immune response was seen in students who were both lonely and isolated, says Pressman. Results were similar for male and female students, she says.

Loneliness and isolation seemed to work independently, says Pressman. Loneliness was also associated with poorer sleep habits and less sleep; Pressman is currently writing a paper about that.

Loneliness, Isolation Are Different

Ever feel lonely in a crowd or content with few people around? It's possible to feel lonely but not isolated and vice versa, says Pressman.

"Social network size wasn't correlated with loneliness," she says. The number of people the students reported having contact with "had nothing to do with how lonely they felt."

"It's not so much the number of people; it's the level of closeness that you feel," Pressman continues. "It really is your perception. If your social network is meeting your needs, then you won't feel lonely."

Familiar Feelings

Pressman says she "absolutely" can relate to the feelings expressed by the students in her study. She remembers feeling that way when she moved far from home to go to college.

Her solution was to get involved on campus, becoming the vice president of her class, joining the psychology society, and participating in dorm activities.

"I really think that helped me," she says. "The faster you can make those connections, the faster you can alleviate those feelings."

Staying in touch with friends and family at home can also help, she says.

People tend to keep the same levels of social integration, says Pressman. In other words, well-connected high school students often build a strong network in college.

"Obviously, there's a period where you have to build those things up," says Pressman.

Others can learn the same skills. "You've got to work on it and get yourself out there," she says. "If you've got people around you, it does seem to buffer this immune detriment."

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Pressman, S. Health Psychology, May 2005; vol 24. Sarah Pressman, MS, doctoral candidate in psychology, Carnegie Mellon University. WebMD Medical News: "Isolated Seniors Prone to Heart Disease." News release, American Psychological Association.