The findings are evidence that the so-called “placebo effect” is at work in recovery from the common cold, which famously has no cure, researchers wrote in the Annals of Family Medicine.
So if the treatment that people believe in — from chicken soup to Vitamin C — does no harm, they might as well stick with it, they added.
“These findings support the general idea that beliefs and feelings about treatments may be important and perhaps should be taken into consideration when making medical decisions,” wrote lead researcher Bruce Barrett, of the University of Wisconsin in Madison.
The placebo effect refers to a phenomenon seen in clinical trials when people given inactive, fake “treatments,” such as a sugar pill or saline — show improvements. It has been observed in a range of conditions, including chronic pain, depression, inflammatory disorders and even cancer.
Barrett and his colleagues randomly assigned 719 people with the beginnings of cold symptoms to one of four groups.
In one group, people were given the herbal cold remedy Echinacea and knew they were taking it. Two other groups were given either Echinacea or a placebo, but participants did not know which they were taking. The fourth group received no pills of any kind.
Overall, there were no significant differences among the groups when it came to the severity or duration of the participants’ symptoms, which lasted about a week in all cases.
But then the researchers focused on the 120 people who, upon entering the study, gave high ratings to Echinacea’s effectiveness.
In that group of Echinacea believers, those who were given pills — Echinacea or placebo — felt better faster. Placebo users recovered a full 2.5 days sooner than their no-pill counterparts, while Echinacea users were cold-free about 1.5 days sooner.
“That’s actually a huge difference. No treatment out there has ever been shown to reduce the duration of colds,” Barrett said.
He added that the findings show more evidence that “what people believe about their medicines matters.
As for the Echinacea, studies have come to conflicting findings about whether the popular herb does in fact work. In an earlier analysis of the same study group, Barrett’s team found that — as in this analysis — Echinacea users in general fared no better than the placebo or no-pill groups.
But there was also no evidence that the Echinacea group suffered side effects. So if you have used it and believe it eases your cold misery, it would “seem reasonable” to continue, Barrett said.
He added that he would like to see more people take simple measures that can make a cold less draining, including getting enough rest, taking plenty of fluids to stay hydrated and eating well — which can include chicken soup.
