Would you feel better if, besides giving you a pill, your doctor also explained some potential benefits?

It's quite likely, according to research from placebo effect studies from the past couple of decades. But an international group of researchers, led by Damien Finniss of the University of Sydney Pain Management and Research Institute in Australia, wanted to take a closer look at just how such an approach affects patients—and doctors who might make use of it.

"The placebo effect is a genuine psychobiological event attributable to the overall therapeutic context," the researchers explained in their review article published online February 18 in The Lancet. In other words, the effect is real but heavily dependent not just on the existence of possible treatment, but perhaps even more so on the environment in which it is administered.

Several types of placebo effects have been identified—from the psychological (conditioning and expectation) to the neurobiological (opioid release and changes in metabolic activity in the brain). But few studies have charted precisely how the clinical context of a placebo or treatment administration changes its effect.

Some studies have shown the effect of "nocebos," which patients are told their treatments might increase discomfort. Others have shown that receiving acupuncture, whether it is real, faked (with retracting needles) or done incorrectly, can better relieve back pain than traditional treatments. But the ethical slope is a slippery one, the researchers conceded, often making further research difficult without ample deception or withholding real treatment from people who need it.

In trials that give drugs to both groups, researchers can study the placebo effect in the way treatment is administered. Some studies have shown that if a drug is injected by a medical practitioner, patients respond better than if it is given at an unannounced time via computer-programmed injections. "The hidden administration removes the psychosocial context of treatment," the authors noted, decreasing patient expectation of relief. And it is hardly a nuanced difference: For example, in a postoperative pain study published in 2001, patients who were given painkillers via a random computer-programmed injection needed a 50 percent larger dose than those who had a person give them the injection.

But clinical trials do not control for many of these aspects of the placebo effect, the review authors argued, and few studies contain a non-treatment group or a group that experiences different clinical handling for comparison with the standard treatment and placebo groups.

Even more worrisome, they reported, with all of the data about the power of the placebo effect now widely recognized, some doctors might be blurring ethical lines by employing it to treat patients without full disclosure. "Routine conscious attempts to identify and exploit features of the clinical encounter to augment placebo effects represent ethical means of applying the understanding of placebo mechanisms to improve clinical outcomes," Finniss and his colleagues noted. But at what point can this treatment tool become deceptive?

Though they might not be sending their patients home with sugar pills, "clinicians often prescribe various active treatments with the main intent of promoting a placebo response," they wrote. Better disclosure might be the solution, they note, but if patients are given a placebo with full disclosure of its inertness—as well as its possible benefits—will it still work as well? The researchers prescribe more clinical research. 

Image courtesy of Wikimedia Commons/Ragesoss