The Nocebo Effect - What It Is, and How to Overcome It
You’ve likely heard of the placebo effect, but have you ever heard of the nocebo effect?
Even if you haven’t heard of it, you’re likely affected by it... maybe even daily. We’ll dig into that in a bit, but first we need to chat about the placebo effect.
The fact that this effect is a part of the scientific process is fascinating to me. The gold standard of clinical trials uses a double-blind placebo: the participant doesn’t know whether or not they have the actual treatment being tested, and the testers don’t know which of the participants have it.
Why would they do this? Because belief changes the results.
I don’t think we talk about this enough. It’s just a given in the scientific process, but it’s such a testament to the power of the mind, and the power of belief.
The placebo effect is so significant that when they are doing clinical trials of new medications, they judge whether or not it’s effective based on whether or not it tests better than the placebo group.
They have to use a group taking a placebo otherwise it could appear the active ingredient was having a positive effect when really... It was all the placebo effect!
Scientists have done testing on the placebo effect itself and have had some crazy results.
In one study, individuals with major depression disorder were given placebo pills labeled as either fasting-acting antidepressants or placebo for one week. After the week, the participants who took the placebo pills labeled as an antidepressant reported a significant decrease in their depression symptoms, and the researchers were able to see on PET scans an increase in brain activity in areas of the brain linked to emotion and stress regulation.
And there are countless more studies like this, all with the same effect: I take this pill that I believe will help me, and so it does.
Here’s where this gets even wilder: this can work even when the person knows it’s a placebo. A study in Scientific Review found that open-labeled placebo (OLP) may reduce fatigue in cancer survivors. The researchers found that participants in the placebo group reported a 29% improvement in fatigue severity and a 39% improvement in fatigue-disrupted quality of life compared to those randomized to treatment as usual.
These patients knew that they were receiving a placebo, and yet many of them still saw significant improvements!
And that’s not the only time this has happened. They’ve used these OLP’s and seen great results in conditions such as back pain, ADHD, allergic rhinitis, major depression, irritable bowel syndrome, and menopausal hot flashes.
The mind is powerful.
Which leads me into the Nocebo effect. This lesser known effect is just as powerful and significant, but it’s kind of the placebo effect’s evil twin. .
Placebo effect = I believe I’ll feel better, and so I do.
Nocebo effect = I believe I will feel worse, and so I do.
This effect has not been studied as thoroughly due to ethical concerns, but there has still been quite a number of findings on this effect.
How might the nocebo effect play out in our everyday life?
You drink a cup of coffee later in the afternoon and tell yourself it’s going to keep you up later. Even though it’s decaf, you’ll struggle to fall asleep that night.
You decide that you didn’t get enough sleep last night and so you walk around groggy and lethargic all day, even though you did get enough REM and Deep Sleep to be sufficiently rested. (This just happened to me the other day! Once I read my sleep results from my Oura ring showing I did get enough sleep, I suddenly wasn’t tired anymore).
In this day and age of “everything causes cancer”, while there’s unfortunately a lot of truth to a lot of those claims… thinking that something will give you a headache, or upset your stomach, or cause even more serious damage, can create an actual physiological change in your body.
One documented case of the nocebo effect happened in 2007 to a 26 year old man who was participating in a clinical trial for anti-depressants. He was rushed to the hospital for overdosing, having taken 29 of the pills he’d been prescribed for the study. His blood pressure dropped dangerously low and he was sweating, shaking, and breathing rapidly - all signs of an overdose. The doctors were able to stabilize him, but after testing his blood, they found zero evidence of drugs in his system.
He had unknowingly been on the placebo side of the trial. His physical reaction followed what he believed would happen from overdosing, not from any outside source.
As I said, we don’t talk about this enough!!
What we believe has such a powerful force on our body. And it makes sense, because our nervous system is constantly preparing for potential threats. It regulates our heart rate and blood pressure, our digestion, our metabolic function, and even our ability to heal.
But our nervous system cannot reason. It can only react.
Just like how you’ll physically jump at a scary part in a movie; your nervous system doesn’t know you’re safe on the couch, it’s reacting to how you feel and what you’re thinking.
All of this being the case, let’s take a moment to reflect:
What kinds of things do you find yourself saying about your body?
“I’m sensitive to everything.”
“I can’t handle stress like other people.”
“If I don’t get 8 hours of sleep, I’m wrecked.”
Some of those might be true and valid. But sometimes the body’s response is magnified, not just by the trigger itself, but by the belief that it will happen.
Tools for Shifting Your Beliefs
If you’ve realized you’re carrying beliefs like “I’ll never heal,” “I’m always the sick one,” or “My body always betrays me,”... first, just pause. Be gentle with yourself. Those beliefs likely came from lived experience. But here’s the good news: beliefs are flexible. They can be updated.
Here are a few tools to start reshaping those old narratives:
Awareness & Curiosity
Notice when those old stories pop up. Instead of judging yourself for them, simply name them. “Oh, I’m telling myself I always get sick on vacation.” Just naming it pulls it out of your subconscious and into conscious awareness, where you have choice. Your thoughts are not you. They are just pieces of data, you get to decide which ones you keep and which ones you let float on by.
Gentle Reframing
You don’t have to force toxic positivity or pretend everything’s perfect. Instead, try a gentle reframe. “I’ve struggled with sickness on past trips, but I’m learning how to support my body better now.” If the fear of what might happen starts to come up, shift from What If to Even If. “Even if that happens, here’s exactly what I can do about it.”
Somatic Anchoring
Beliefs live not just in the mind but in the body. Use a grounding practice like deep breathing, hand on heart, or tapping while you practice a new, more supportive belief. This helps your nervous system feel the shift, not just think it. Listen to binaural beats while you focus on the beliefs you want to have. (Great to do this with affirmations when you first wake up to rewire the brain as it’s in a more pliable state!)
Evidence Collection
Look for small wins and moments that challenge the old story. Did you go to a social event and not come home wiped out? Did you eat something new and feel okay? Celebrate those moments! Your brain needs evidence to update its beliefs. Remember that so much of what we see is based on perspective, not on reality! When we’re actively searching for those happy moments, they’re there for the finding.
When you can understand that your reactions aren’t random, that they’re part of a system designed to keep you safe, it shifts you from fear into curiosity.
And curiosity opens the door to healing.
