Friday, April 17, 2009
Some researchers at McGill University recently issued the results of a study completed on the level of response to a placebo that various personalities had. According to a story in the New Scientist Health, personality type does in fact impact the degree of response to a placebo that an individual experiences. Ewen Callaway writes,
If rollercoasters and rock concerts sound fun but leave you with a headache, a drug-free sugar pill might be all that's needed to soothe you. Thrill-seekers enjoy a stronger placebo response than people with more restrained personalities, new research shows.
It's too early to prescribe phoney pain treatments based on personality tests, says neuroscientist Petra Schweinhardt, of McGill University in Montreal, whose team tested 22 male university students. But if confirmed in larger trials, her team's findings could help pharmaceutical companies avoid testing experimental drugs on people with strong placebo responses, she says.
Her team injected a pain-inducing saline solution into the left and right legs of willing volunteers for 20 minutes. "It's a dull pain, a dumb pain, it's aching, it's annoying," she says. Before the injection, her team told volunteers they were testing an experimental analgesic cream – really just skin lotion. To make the ruse more believable, researchers said they would test one leg with the treatment and one leg with a non-medicated lotion. . . .
"We really told them the whole story in order to counteract any doubts in the treatment," Schweinhardt says. Volunteers then rated their pain across both trials, and the difference amounted to the placebo response. Not everyone got pain relief from the placebo, but those that did scored higher on tests that gauge sensation-seeking personalities. These characteristics explained about a third of the differences in placebo responses between volunteers.
"The fact that they show a pretty strong correlation between a personality trait and strength of placebo response, I do find interesting," says Jon Stoessl, a neurologist at the University of British Columbia, who has studied placebo response in patients with Parkinson's disease. But he notes that a person's placebo response can change over time and varies depending on the condition, so personality alone probably won't explain his or her response. "If whatever condition you're suffering from is severe on one occasion and really a minor nuisance on another occasion, that could affect the degree of placebo response," he says. . .