Caffeine and Parkinson’s: One researcher, two studies, and opposite results. What happens?

Michael Joyce produces multimedia at and tweets as @mlmjoyce

coffee Parkinson's

In August of 2012, Ronald Postuma, MD, a neurologist from McGill University, performed a study along with several coauthors which suggested that caffeine improves debilitating movement symptoms in people with Parkinson’s disease.

News coverage was brisk and included major outlets like Reuters, CBS News, Huffington Post, and Fox News (running the Reuters story).

Yesterday, Dr. Postuma published his long term follow-up results in a larger group of patients which — contrary to the previous study — did not show any improvement with caffeine.

Consumer-focused news coverage of these new “negative” findings – as of today – is not nearly as brisk as coverage of the “positive” findings was five years ago.

HealthDay reported on both studies, and US News ran HealthDay’s wire story on the most recent trial as well as its own take on the 2012 research.

But of the other major outlets who jumped on the story five years ago, none has posted coverage that we could find about the new study. Why?

What’s Wrong with Uncertainty and Caution?

Before we can speculate as to why coverage is leaner this time around, there are some important lessons to consider from the 2012 coverage.

Looking back, I would say that the coverage was quite good. In fact, several reporters — as well as the writers who penned the news release for Neurology (which published both the 2012 and 2017 McGill research) — were appropriately cautious in including the following:

  • A few quoted author Postuma as warning that the 6-week duration of the study, as well as the study group size of just 61 Parkinson’s patients, made it difficult to know if the positive effects would last.
  • Likewise, Postuma appropriately speculated that tolerance to caffeine may limit its long term benefits on movement symptoms
  • Many reporters included the fact that the existing treatment of choice for movement problems in Parkinson’s Disease — levodopa — has a benefit 3 to 4 times greater than the documented caffeine effect.

This is good reporting. And it led many journalists to make the following caveats quite clear: more research is needed, with more subjects, and more time.

And as we now know, they were right to do so.

Why This Matters

These two studies, not just separated by 5 years, but also distinguished by contrary findings, teach us some valuable lessons.

First, this is how science progresses. It’s not so much about clear-cut answers as it is about constantly questioning. In this case, the 2012 results were promising for a “positive” effect on a disease that sorely needs some good news. But, the researchers (and many of the journalists) were not satisfied and needed to know if these results were verifiable and reproducible. It ends up they were not. Although that “negative” result may not feel as optimistic or impactful as the previous “positive” result, it’s still important information. It’s not only more accurate information, but it will help focus further research.

brain dementia mental healthAnd this brings us to an important point about so-called “negative” results. When medical journals, academic PR departments, or news organizations avoid publishing negative results — presumably because they lack the allure or gravitas of positive results — they’re not just revealing ignorance of the scientific method, but are also severely compromising public opinion and discourse by providing incomplete information. People make decisions about their health based on what they read in the news; if that news is slanted toward positive findings, the public doesn’t have a solid foundation for making good choices.

We’ve covered this before (HERE).

“All My Patients Started Drinking Coffee!”

Ronald Postuma, MD

Looking back on the quotes provided by Postuma – both this week and five years ago – it struck me that he presented his work cautiously and without self-promotion. This type of restraint isn’t necessarily the norm among researchers discussing their work. I asked him if there were any differences between the coverage five years ago and this week that struck him.

“I’d guess we got two to three times more coverage of our positive findings five years ago,” said the McGill neurologist. “That positive results are seen as news or more clickable, while negative results are not news, doesn’t surprise me.” But he was surprised by something else:

“I always try to include caveats and limitations. And most of the reporters included them and were accurate. But, nonetheless, all my patients started drinking coffee. Even when I told them these were just preliminary findings. That surprised me. This one doesn’t fall on the reporters. Because between what they write, and what goes into people’s heads, there’s often a disconnect. Readers often seem to want to remember one or two things, then our warnings and caveats disappear, and they select what becomes fact in their brain.”

Postuma’s mea culpa notwithstanding, doesn’t some of this fall on the reporters? As well as the PR people and everyone else in the news-making food chain involved with communicating study findings to the public?

As we know, provocative results from small, preliminary studies are very often overturned or significantly revised by subsequent, more rigorous research. And yet, Postuma’s patients were ready and eager to adopt changes based on such early, preliminary research, despite all the warnings and caveats that were appropriately conveyed by journalists and experts.

It’s another example that should make journalists reflect about how they frame the results of such studies, and whether they should be more selective about which studies get promoted to the public in the first place.

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