Study Underscores Power of Placebo Effect

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A new study — this one involving patients with Parkinson’s disease — adds another layer of insight to the well-known “placebo effect.” That’s the phenomenon in which people’s symptoms improve after taking an inactive substance simply because they believe the treatment will work.

The small study, involving 12 people, suggests that Parkinson’s patients seem to feel better — and their brains may actually change — if they think they’re taking a costly medication.

On average, patients had bigger short-term improvements in symptoms like tremor and muscle stiffness when they were told they were getting the costlier of two drugs.

In reality, both “drugs” were nothing more than saline, given by injection. But the study patients were told that one drug was a new medication priced at $1,500 a dose, while the other cost just $100 — though, the researchers assured them, the medications were expected to have similar effects.

Yet, when patients’ movement symptoms were evaluated in the hours after receiving the fake drugs, they showed greater improvements with the pricey placebo.

What’s more, MRI scans showed differences in the patients’ brain activity, depending on which placebo they’d received.

None of that is to say that the patients’ symptoms — or improvements — were “in their heads,” experts stressed.

“Even a condition with objectively measured signs and symptoms can improve because of the placebo effect,” said Dr. Peter LeWitt, a neurologist at Henry Ford West Bloomfield Hospital, in Michigan.

And that is “not exclusive to Parkinson’s,” added LeWitt, who wrote an editorial published with the study that appeared online Jan. 28 in the journal Neurology. Research has documented the placebo effect in various medical conditions, he said.

“The main message here,” LeWitt said, “is that medication effects can be modulated by factors that consumers are not aware of — including perceptions of price.”

In the case of Parkinson’s, it’s thought that the placebo effect might stem from the brain’s release of the chemical dopamine, according to study leader Dr. Alberto Espay, a neurologist at the University of Cincinnati College of Medicine.

Parkinson’s disease arises when brain cells that produce dopamine become dysfunctional, leading to movement symptoms such as tremors, rigid muscles, and balance and coordination problems.

And it so happens that the brain churns out more dopamine when a person is anticipating a reward — like symptom relief from a drug.

To Espay, the new findings are more evidence that “expectations” play an important role in treatment results.

“If you expect a lot, you’re more likely to get a lot,” he said.

The patients in his study didn’t get as much relief from the two placebos as they did from their regular medication, levodopa — a standard Parkinson’s drug.

But the magnitude of the expensive placebo’s benefit was about halfway between that of the cheap placebo and levodopa, according to the researchers. What’s more, patients’ brain activity on the pricey placebo was similar to what was seen with levodopa.

So does this mean that the many expensive drugs on the market work only because people think they will?

LeWitt doubted that. New drugs are approved because they outperform placebos in clinical trials, he said.

But the reality, LeWitt noted, is that people tend to have certain beliefs about medications that may sway their effectiveness.

He said research shows that consumers often think large pills work better than smaller ones, brand names outperform their generic equivalents, and even that red pills fight pain better than blue ones.

The 12 patients in this study had their movement symptoms evaluated hourly, for about four hours after receiving each of the placebos. It’s not clear whether the symptom improvements would hold up in the long term — but Espay said that as long as patients kept believing in the “drugs,” they might.

According to Espay, there is potential for doctors to use the placebo effect to help patients with Parkinson’s, or other conditions, fare better on their treatments.

He said it could be as simple as mentioning that a new prescription is expensive, even if it’s not $1,500 a dose. For many people, the “cheap” placebo in this study would seem costly, he noted.

But Espay also pointed to a bigger message from research on placebo effects: People’s mindsets do have power in how well they fare with a disease.

“A big part of patients’ prognoses has nothing to do with us doctors,” he said.

The study was scrutinized by the university’s review board before it began because it called for deceiving the participants. The board found that the study met federal research regulations, and the deception would have no adverse effects on the participants’ welfare, according to the journal editors.

More information

The Parkinson’s Disease Foundation has more on treating Parkinson’s.

Source: HealthDay

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