Can a placebo, or dummy pill, help patients who are informed that they will be getting a placebo?

That was the intriguing question posed by U.S. researchers, who conducted a small pilot study of 80 patients suffering from irritable bowel syndrome.

At the end of three weeks, they found that placebos administered without deception did appear to have an effect on patients who self-reported their symptoms.

But there was a little more to it than just handing out the placebos -- in this case, microcrystalline cellulose pills.

Subjects were recruited through ads and referrals by health-care professionals asking for participants for a novel mind-body management study of IBS. Indeed, one observer notes that this could be a limitation to the study, in that this wording may have attracted impressionable patients.

A control group of 43 got no treatment, while 37 patients got open-label placebo -- they were told they were getting an inert substance that contained no medication and that the placebo effect is powerful and the body can automatically respond to such pills like Pavlov's dogs who salivated.

In addition, they were told that taking the pills faithfully is critical, and a positive attitude helps but is not necessary.

Researcher Ted Kaptchuk, associate professor at Harvard Medical School's Osher Research Center, said he had to convince -- actually beg -- his colleagues to take on the unusual project.

"We weren't even sure that we could recruit patients. That was our first goal -- to see if anyone would even come into the study. And we were able to recruit patients easily," he said in an interview.

"And then we got this incredible result."

Fifty-nine per cent of patients treated with placebo reported adequate symptom relief, compared to 35 per cent in the control group.

On other outcome measures, patients taking the placebo doubled their rates of improvement to a degree roughly equivalent to the effects of the most powerful IBS medications, said a release.

The findings were published Wednesday in the online medical journal PLoS One.

"Basically we wanted to see whether this conventional wisdom that you need to lie to patients to get the placebo effect is true," said Kaptchuk, who did the work with colleagues from Beth Israel Deaconess Medical Center.

"And to our surprise, to some extent, I'd say we were really flabbergasted by the magnitude of the effect we got in this little study. People get better even if they know it's placebo."

However, he said the findings need to be treated with caution, and aren't definitive.

"This is a pilot study to test whether this is worth investigating more," he said.

A recent U.S. survey of internists and rheumatologists found that very few doctors secretly use inert placebo pills and injections. However, about half of respondents prescribe medications that they don't expect will help their patients' conditions and which are used, in effect, as placebos.

John Fisk, a clinical psychologist at Capital Health in Halifax, described it as a good study but agreed there's a need for further work to demonstrate this in other populations and with larger sample sizes and other medical conditions.

He said the study shows that if people believe that taking a sugar pill is potentially going to be therapeutic for them, and they notice an improvement in their symptoms, then they may well attribute it to taking the sugar pill.

"It really does bring home the importance of empowering people in terms of doing something to control their condition," said Fisk, who was a member of the National Placebo Working Group a few years ago.

"I think that the key point here is that yes, it's placebo, but they're also telling people that this is a placebo, but it's a demonstrated effective treatment."

It would be interesting to compare taking a placebo, as this study has done, with some other intervention such as an exercise program "which is, for example, going to make people feel potentially better, give them the same sense of control," said Fisk, an associate professor in the department of psychiatry at Dalhousie University.

Kaptchuk said his group is beginning pilot studies on placebos without deception for patients with two other diseases, and he hopes for funding to replicate these results in a larger study.