sábado, março 15, 2008

Um mundo ou o mundo?

Dying for company
By Stephen Pincock
One morning in the spring of 1994, John Cacioppo, a psychologist at Ohio State University, pushed back his chair and set off for a solitary walk around campus. Cacioppo does his best thinking on his feet, and that day he had a nagging scientific question to ponder. For years, he and others had been looking at how the brain processes information and how those processes determine physiological reactions in the body. But Cacioppo was beginning to feel that a tight focus on mind-body interactions left an important factor out of the equation. “It had dawned on me that our inquiries had stopped at the cranial vault,” he remembers. “But so much of what makes us human goes beyond the brain as an information-processing organ.” Cacioppo wanted to consider a third factor: how our life as social animals – how society itself, even – had shaped the human brain, and how that in turn had affected our health, both now and through the ages.
It was a fine day, and crisp sunlight was shining through the first pale leaves on the trees nearby. As he wandered along the shore of a small lake, Cacioppo realised that in order to investigate the importance of social connections on the brain, he needed to observe people who lacked those connections – to study the extreme cases to determine the extent to which all our brains are shaped by social interaction. In other words, he needed to study loneliness.
We all feel the pang of loneliness now and again. Surveys show that about 80 per cent of people admit to occasional moments of loneliness. For most, it’s a fleeting sensation. The phone rings, a friendly hand taps your shoulder, the feeling passes. But for others, loneliness can be a long-term companion. Roughly one in four people experiences the persistent feeling that their social relationships aren’t what they’d hope them to be.
This may not come as a surprise. What’s less often appreciated, however, is that chronic loneliness has consequences beyond emotional misery. In recent decades, scientists have repeatedly found that people who experience chronic feelings of loneliness suffer physically as a result.
The list of medical ailments linked to loneliness is long and unpleasant. One group of researchers found that people with few social ties were more susceptible to common colds; another group recently showed that socially inhibited people with HIV responded less well to anti-Aids drugs.
Along the same deadly lines, socially isolated women are at greater risk of dying after being diagnosed with breast cancer. Living alone is a risk factor for recurrent heart attacks and death from cardiac causes, and lonely people don’t sleep as well. Last year it emerged that people who are lonely in their old age are twice as likely to develop Alzheimer’s disease as their socially active counterparts.
That lonely people are at significantly higher risk of dying early is not an entirely new discovery. In 1977 the US psychologist James Lynch sounded a warning in his book, The Broken Heart, about what happens in societies where people don’t share their thoughts, hopes and feelings with one another. “The choice is ours to make,” he wrote. “We must either live together or face the possibility of prematurely dying alone.”
But how does a psychological condition such as loneliness have such dramatic physical consequences, and what could those consequences tell us about how the brain – and not just the brains of lonely people – works? Those were the questions Cacioppo wanted to answer.
The prevailing wisdom, when he began researching the topic, was that a sort of Bridget Jones effect was to blame: that simply sitting alone on the sofa eating tubs of ice-cream makes you unhealthy – which is true. It’s also true that lonely people are less likely to engage in physical activity and less likely to call on others when they need help.
But Cacioppo thought these “health behaviours” were only a small part of what was going on. His theory was that loneliness must influence our long-term health in more fundamental and interesting ways. So began a research programme that is still going, 14 years after Cacioppo’s lakeside stroll. During that time, he and his colleagues – now at the University of Chicago – have been teasing out the links between our social, emotional, neurological and physiological selves – what he calls social neuroscience.
Cacioppo says one of the first realisations his group came to was that there is a great difference between isolation and loneliness. “For the most part, the more interesting pathways we’ve been studying are tied to perceived isolation,” he says. “In most people, the perceptions [of how isolated they are] are driving other brain and genetic processes.”
One of the most important clues suggesting there’s something biological linking loneliness and poor health is the fact that many illnesses linked to loneliness – cancer and heart disease, for example – seem to occur alongside a similar biological problem. They all involve inflammation. But this connection presents a conundrum: lonely people also tend to have high levels of stress hormones in their bloodstream, and stress hormones are known to reduce inflammation.
“We know that these shy, sensitive, lonely people are getting sick and dying of inflammation-related diseases,” says Steve Cole from the University of California, Los Angeles. “Yet the stress hormones should be protecting them from those kinds of adverse effects.”
Cacioppo, Cole and others have begun to trace a filigree of cause and effect that offers a mechanical explanation for how the social and emotional elements of loneliness might directly affect our health.
Each year, 200 people from the Chicago region volunteer to visit the lab Cacioppo runs with his colleague Louise Hawkley and undergo an exhaustive series of surveys, tests and measurements. In one of the researchers’ investigations they studied a sub-group of the study participants, seven of whom had been rated among the least lonely and another seven who had returned the highest loneliness scores. From each person they took a sample of blood and used DNA technology to study their white blood cells, the cells that co-ordinate inflammation and immune responses. They found that loneliness seemed to be linked to changes in the activity of a group of 209 genes.
The changes were far from random. Genes involved in stimulating the immune system – and so causing inflammation – were more active in the more-lonely group, while genes that suppressed inflammation were less active. The researchers had found the genetic reason why lonely people, who have high levels of stress hormones in their blood, were not seeing their inflammation reduced, as one would expect. Inflammation was “running amok as a consequence”, says Cole, and so were the diseases associated with it.
But it isn’t only the inflammation genes that seem to be affected by loneliness. The researchers also found that two groups of genes that help defend against infectious diseases were under-expressed in people who felt chronically lonely. The first of these produces molecules called Type 1 interferons, whose role is to fight off viruses. The other is a group of genes for antibodies, which are used by the immune system as tags to identify foreign objects that need to be eliminated. “At the same time that the immune system is over-hyping the amount of danger in the body with these inflammatory signals, it’s under-responding to some of the key kinds of pathogens that the body confronts,” says Cole.
. . .
For Cacioppo, understanding this web of biological effects has led to a fundamental re-evaluation of loneliness. “When I started studying loneliness, it was viewed to be a kind of unpleasant state with no redeeming qualities. Others treated it as the same thing as depression, still others as the same thing as introversion,” he says. “We have found that these characterisations were incorrect.”
Cacioppo has come to the conclusion that, by compelling us to seek out our fellow humans, loneliness has played a central role in the development of society – an idea he expands upon in a book to be published this year. Working together in a collective, he explains, allowed our evolutionary predecessors to divide up labour, protect themselves against predators and generally survive. “The pain of loneliness, the dysphoria of loneliness and the hostility caused by loneliness are all because being connected is so integral to human survival.”
For us humans, being isolated is dangerous, Cacioppo explains. So the feeling of loneliness can be seen as a prompt that encourages you to seek out others – “We liken it to physical pain” – which alerts us to bodily harm. “Without physical pain you’re not likely to survive long.” And yet, just as people can develop chronic pain with no discernible physical cause, so some people become lonely despite being surrounded by people, he says. When the “loneliness switch” gets stuck in the “on” position, a normally healthy reflex becomes deadly.
Working with twins in the Netherlands, the Chicago researchers have tried to understand what causes that loneliness “switch” to get stuck – and they found that a predisposition to loneliness is partly inherited from your parents. Genetics account for almost 50 per cent of a person’s likelihood of experiencing serious lonely feelings, while the remaining half is caused by the experiences they have during their life.
Ultimately, spending his working life observing lonely people has brought Cacioppo a philosophical perspective on their behaviour – and human behaviour more generally. “When I see lonely people doing these not-so-nice things, I like them more,” he laughs. “I like them more because I realise that the pain they’re being subjected to contributes to all of us being human. I’m more sympathetic to them than I used to be, and I’m more sympathetic to myself when I feel that way.”
As a society, he says, we all ought to be more sensitive to those individual differences in people’s need for social connections. “I think we have it wrong as a culture. Right now we think that if you have an opportunity to move across the country to get a promotion you’d be neurotic or weak if you didn’t do it. That’s a little bit like telling someone who’s salt-sensitive they’re being neurotic for not eating salt and then, if they start eating salt again, blaming them for getting cardiovascular disease.”
Thinking about loneliness in these terms also offers some consolation for those of us who succumb to loneliness, whether fleetingly or otherwise. Although it may be more or less unavoidable, it’s where our humanity came from. As Cacioppo says: “We can get stuck, but one of the ways to get unstuck is to be sensitive to how important it is in the first place.”

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