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【Science】孤独症
http://www.sciencemag.org/content/331/6014/138.full
Everyone knows what it's like to be lonely. It often happens during life's transitions: when a student leaves home for college, when an unmarried businessman takes a job in a new city, or when an elderly woman outlives her husband and friends. Bouts of loneliness are a melancholy fact of human existence.
But when loneliness becomes a chronic condition, the impact can be far more serious, says John Cacioppo, a social psychologist at the University of Chicago in Illinois. Cacioppo studies the biological effects of loneliness, and in a steady stream of recent papers, he and collaborators have identified several potentially unhealthy changes in the cardiovascular, immune, and nervous systems of chronically lonely people. Their findings could help explain why epidemiological studies have often found that socially isolated people have shorter life spans and increased risk of a host of health problems, including infections, heart disease, and depression. Their work also adds a new wrinkle, suggesting that it's the subjective experience of loneliness that's harmful, not the actual number of social contacts a person has. “Loneliness isn't at all what people thought it was, and it's a lot more important than people thought it was,” Cacioppo says.
Colleagues credit him with building an impressive network of collaborations with researchers in other disciplines to pioneer a new science of loneliness. “He's placed it on the scientific map,” says one collaborator, Dorret Boomsma, a behavioral geneticist at Vrije Universiteit Amsterdam in the Netherlands. “He's doing very creative work,” says Martha Farah, a cognitive neuroscientist at the University of Pennsylvania. “He's created a new way of thinking about the biology of interpersonal relationships.”
A new beginning
\Cacioppo hasn't always studied loneliness. In the 1980s and '90s, he made a name for himself with meticulous laboratory studies on various aspects of emotion and cognition, and he's a founder of the field of social neuroscience, which seeks to understand the brain's role in social behavior. (Last month, colleagues elected him president of the newly formed Society for Social Neuroscience.)
Cacioppo says a 1988 Science paper suggesting that social isolation increases mortality (29 July 1988, p. 540) prompted him to change the focus of his research. Since then, scores of studies have found that people who lack social support are more prone to a variety of ailments. An analysis of 148 of these studies, published in the July 2010 issue of PLoS Medicine, suggests that social isolation increases the risk of death about as much as smoking cigarettes and more than either physical inactivity or obesity.
Compelling as these epidemiological studies are, Cacioppo says, they leave unanswered many questions about the mechanisms involved and about what aspects of social isolation are responsible. In the early 1990s, he set out to tackle these questions. He began by handing out questionnaires to thousands of students at Ohio State University in Columbus, where he was based at the time, and following up with physiological and psychological testing in the lab. For the past 10 years, he has been testing hundreds of Chicago-area residents, working closely with psychologist Louise Hawkley and other University of Chicago colleagues.
This work has convinced Cacioppo that loneliness is a health risk on its own, apart from conditions such as depression or stress that are common fellow travelers. More specifically, it seems to be the subjective experience of loneliness that's important for people's well-being rather than any objective measure of social connectivity (the number of close contacts someone has, for example). It's an important distinction that most previous studies had ignored, says Daniel Russell, a psychologist at Iowa State University in Ames. “Some people are socially isolated and they're not lonely,” Russell says. “By contrast, some people are lonely even if they have a lot of social contacts.”
As a graduate student in the 1970s at the University of California, Los Angeles (UCLA), Russell helped develop the scale Cacioppo now uses in most of his research. The UCLA Loneliness Scale is based on a questionnaire that tries to size up how people perceive their social situation, with questions about how often they feel a lack of companionship, feel they have no one to talk to, or feel out of tune with those around them.
Sympathetic feelings
When people score high on the UCLA Loneliness Scale, Cacioppo and colleagues have found, they also tend to exhibit several physiological changes that effectively put the body in a state of alert. In one early study, they found that lonely people exhibit higher vascular resistance, a tightening of the arteries that raises blood pressure. That forces the heart to work harder and can contribute to wear and tear on vessels.
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作者:admin@医学,生命科学 2011-01-15 11:45
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