We've done two episodes on the placebo effect, but there's a new study that just came out that we've gotta touch on. It's called "Placebo effect of medication cost in Parkinson's disease."

Parkinson's disease is a chronic condition that leads to tremors or uncontrollable shaking. These can make it difficult to do lots of things, like walk or make purposeful movements. It can also lead to neurologic issues, like dementia and mood disorders.

There's no cure, but medications and surgery can sometimes provide some symptom relief. The side effects from those drugs can be pretty bad, though. That's where this study comes in.

Researchers took a bunch of patients with Parkinson's disease, average age 62 years old, and gave them injectable saline, or a placebo. They told half of them they were getting a "cheap" new drug and the other half they told they were getting an "expensive" new drug.

Then they measured them on a number of physical tasks. So this wasn't just "How does it make you feel?" They measured how much their physical movements improved. Four hours later, they reversed the groups, telling them they were getting the opposite drug.

Everyone got better with both of the placebo injections--that's placebo effect number one. But those who got the "expensive" drug got more of an effect.

In fact, quoting the study, "expensive placebo significantly improved motor function and decreased brain activation in a direction and magnitude comparable to, albeit less than, levodopa." And L-dopa's like, the real drug.

Now, this is a small study. And not the kind of thing I'd promote to change our prescribing behavior or beliefs. But it's another data point. And a reminder of the power of the placebo effect.

Unless you're truly out of touch, you've probably heard that there's a measles outbreak in the United States right now. This is how an outbreak of a disease that isn't endemic to the United States occurs:

1. Someone traveling or living abroad contracts the disease and comes to the United States.

2. Other people who are susceptible to the disease come into contact with that person from number one, here at home.

3. Those people contract the disease.

4. Go back to step two.

That's it. It doesn't matter if the person from step one was an illegal immigrant, a doctor working overseas, or an Amish missionary. Since we can't control what other countries do and we live in a world where people travel, step one is going to occur at some point.

What we can do is try to prevent other people here from getting the disease, and that's where vaccination comes in. If everyone is vaccinated against measles, for instance, then yes, a very small number of people might contract the disease when [step] two occurs, but the vast, vast majority of people who come into contact with the infected first person will be fine.

This system breaks down and outbreaks occur when more people are susceptible. Everyone, for instance, is susceptible to Ebola at a certain point in that illness. So we have to be careful to quarantine people who are infected when they're sick.

But Ebola is relatively hard to catch. It has an R₀ of 2, meaning that an infected individual might infect, on average, two others. But measles has an R₀ of 18. It's one of the most infectious pathogens around.

Quarantining is difficult, if not impossible. The virus is unbelievably hardy and very easy to catch. So the absolutely positively best thing you can do is to be vaccinated.

I should also point out that it also doesn't matter to the outbreak why people remain unvaccinated and susceptible. It can be because of religious reasons. It can be because of an irrational fear. It can be because they're hippies. I don't care; the outbreak is the same.

Step one is gonna happen. But if everyone was vaccinated, then the infected person wouldn't make national news because it would be very hard for it to go much beyond themselves.

The important part of stopping an outbreak of measles isn't the traveling person--that's gonna happen every once in a while. The important part is that too many people remain unvaccinated and susceptible to measles for any number of reasons. That's what's causing the outbreak. That's what we need to focus on. Full stop.

But berating people who don't vaccinate their children won't help. Be respectful. Talk about the facts. There are plenty to be found here on Healthcare Triage.