Jane McCredie: Honest placebos

THERE is one treatment for conditions ranging from depression to back pain to irritable bowel syndrome that produces impressive results with minimal side effects. Yet clinicians are often reluctant to prescribe it.

Why? Because this particular silver bullet is the placebo effect.

Although the mechanisms of placebo remain largely mysterious, the belief that we are receiving a helpful treatment somehow seems to have the ability to make us feel better.

And there’s the rub. If we need to believe in it for placebo treatment to work, then surely the clinicians dispensing it would have to practise a certain level of deception.

But maybe it’s not that clear cut.

Canadian psychologist Dr Susan Huculak argues we need more open discussion about the role of placebo in medicine as well as clear guidelines for clinicians on how and when to use it.

Competing viewpoints on placebo — from scorn to veneration — have impeded progress, Huculak writes in an opinion article that uses psychiatry as a case study.

Clinical trial researchers tend to see placebo as no more than a contaminant, and they strive to design trials to minimise its effects, she writes, quoting one research team writing that the placebo “problem” is “probably the most common reason for negative trials”.

So it’s not the “drugs not working as they’re supposed to” problem that’s at fault here then. Phew.

In any case, Dr Huculak asks, should researchers be seeking to reduce the placebo effect in the first place?

“If the effects following placebo are as real and potent as the drug effects (ie, are legitimate), it would make little sense to try and reduce them”, she writes.

This may be particularly relevant in psychiatry where a number of studies have shown antidepressants are no more effective than placebo in mild to moderate depression, despite showing efficacy in severe depression.

Given the known side effects of antidepressants, should we be exploring placebo as a treatment in less-severe forms of the disease?

Clinicians, Dr Huculak writes, are “generally uncomfortable or even baffled” when it comes to the placebo effect.

Despite that discomfort, several studies have suggested many doctors do use placebos in clinical practice — whether it’s a recommendation of vitamins, an unwarranted prescription for antibiotics, or a subtherapeutic dose of antidepressants.

One of the reasons for the enduring popularity of alternative health therapies may be that the practitioners are particularly skilled at stimulating a placebo response.

Deliberate use of a placebo without the patient’s knowledge raises clear ethical issues, but is deception always necessary for the placebo effect to work?

It seems extraordinary, but maybe not.

Researchers from the Harvard Medical School conducted a controlled trial in irritable bowel syndrome, with placebo as the active treatment. The control in this case was no treatment at all, though participants in both arms received the same level of interaction with providers.

Participants in the active treatment (ie, placebo) arm of the trial were told they were being given “placebo pills made of an inert substance, like sugar pills, that have been shown in clinical studies to produce significant improvement in IBS symptoms through mind-body self-healing processes”.

Those given the sugar pills experienced significantly greater improvements in their condition than those who did not get the placebo.

So there’s the question: could openly giving a placebo, accompanied by the information that placebos have been shown to work, offer an ethical way to harness this powerful tool?
 

Jane McCredie is a Sydney-based science and medicine writer.