Placebos In and Out of Trials

Does it make a difference if a placebo is taken as prescribed by your family physician or as part of a clinical trial?

In the setting of double-blind placebo-controlled clinical trials (DBPC), placebos are prescribed with the hope of helping the trial answer a specific question, not in an attempt to help the individual patients who are taking placebos get or feel better. In contrast, in medical practices placebos are prescribed with hope of helping patients get or feel better when no effective therapeutic options are available or the physicians believe their patients' symptoms are psychosomatic.

In trials, neither the physician-researcher nor the patient knows whether a particular patient is receiving the experimental drug or an inactive placebo. Not so in clinical practice, where the physician knowingly prescribes an ineffective treatment to patients who believe they are taking effective treatment.

In trials, patients don't know what to expect, because they signed an informed consent form agreeing to the possibility of receiving a placebo. In the clinical practice setting, patients expect a good result from taking what they believe is active medicine from their trusted physician. 

In trials, the researchers and patients accept that it is unknown if the drug will prove to be better or no better (or worse) than standard therapy. These patients feel the hope of possibly benefiting from cutting-edge science that improves on standard therapy. In clinical practices, patients feel the hope associated with FDA-approved therapies.

Research has reported that the magnitude of the placebo effect varies according to factors that affect patients' hopes and expectations. All other things being equal (e.g., size and color of pill, the appearance of physician, location of clinic, etc.), you would expect the placebo effect in trials to be different than the placebo effect in practice, don't you think?

Comments

[Thomas A. Warr, MD]

Dear Wendy,

You did a nice job of contrasting the two situations - in clinical research and in routine clinical practice - where a placebo might be used. Thanks - I agree with your assessment.

Interestingly, placebos might not always be totally benign. In the prostate cancer prevention trial we participated in a few years ago, the "sugar pill" contained lactose. Some of the subjects were lactose intolerant and couldn't take it.

Best regards, Tom Warr

[Wendy S. Harpham, MD]

Dear Dr. Warr,

This blog encourages me look more closely at ideas and definitions that for years I've taken for granted.

We use the term "sugar pill" colloquially for "placebo." But technically, as your experience in the prostate ca prevention trial demonstrates, the sugar pill may not be a good choice for a placebo since it wasn't inert.

I can think of emotional side effects/aftereffects related to the taking of placebos, too. Your thoughts?

With hope, Wendy