The Nocebo Effect: How Negative Thoughts Can Harm Your Health

Most of us have heard of “the placebo effect,” the heal-inducing effect patients in clinical trials experience when they believe they’re getting a fancy new drug or surgery but are actually getting fake treatment. The placebo effect is real, it works about 18-80% of the time, and it’s not just in your head – it actually dilates bronchi, heals ulcers, makes warts disappear, drops your blood pressure, and even makes bald men who think they’re getting Rogaine grow hair!

Unwanted Side Effects

But the placebo effect has a shadow side. The same mind-body power that can heal you can also harm you. When patients in double-blinded clinical trials are warned about the side effects they may experience if they’re given the real drug, approximately 25% experience sometimes severe side effects, even when they’re only taking sugar pills.

Those treated with nothing more than placebos often report fatigue, vomiting, muscle weakness, colds, ringing in the ears, taste disturbances, memory disturbances, and other symptoms that shouldn’t result from a sugar pill.

Interestingly, these nocebo complaints aren’t random; they tend to arise in response to the side effect warnings on the actual drug or treatment. The mere suggestion that a patient may experience negative symptoms in response to a medication (or a sugar pill) may be a self-fulfilling prophecy. For example, if you tell a patient treated with a placebo he might experience nausea, he’s likely to feel nauseous. If you suggest that he might get a headache, he may. Patients given nothing but saline who thought it was chemotherapy actually threw up and lost their hair!

When You Think You’re Going To Die…

In another study, patients about to undergo surgery who were “convinced” of their impending death were compared to another group of patients who were merely “unusually apprehensive” about death. While the apprehensive bunch fared pretty well, those who were convinced they were going to die usually did.

Similarly, women who believed they were prone to heart disease were four times more likely to die. It’s not because these women had poorer diets, higher blood pressure, higher cholesterol, or stronger family histories than the women who didn’t get heart disease. The only difference between the two groups was their beliefs.

The nocebo effect is probably most obvious in “voodoo death,” when a person is cursed, told they will die, and then dies.  The notion of voodoo death doesn’t just apply to witch doctors in tribal cultures. The literature shows that patients believed to be terminal who are mistakenly informed that they have only a few months to live have died within their given time frame, even when autopsy findings reveal no physiological explanation for the early death.

Dr. Steve’s Story

In response to what I said in my latest TEDx talk about the placebo effect’s evil twin, “the nocebo effect,” L. Chas sent me an email, telling me the story of her brother Steve, who was a physician diagnosed with the exact same illness that was his specialty. When he was diagnosed with malignant tumors in both lungs, he was told by his doctors that he had five years to live, and knowing what he knew about the disease, Steve believed this.

Exactly 5 years later, to the day, he was snorkeling in Maui when he was found, unconscious on the shore. Steve was resuscitated, but he had been without oxygen to the brain for over four minutes and wound up in a coma until his family chose to withdraw life support.

L. Chas wrote, “More than anything else, I think my brother believed that, when diagnosed with his disease, a patient has ’5 good years left’.  Just as you’ve said in your videos – the nocebo effect. So sad it had to go this way.”

Medical Hexing

Every time your doctor tells you you have an “incurable” illness or that you’ll be on medication for the rest of your life or that you have a 5% five year survival, they’re essentially cursing you with a form of “medical hexing.” They don’t mean to. They’re not trying to harm you. They know not what they do…

Doctors think they’re telling it to you straight, that you deserve to know, that you should be realistic and make arrangements, if necessary. But when they say such things, they instill in your conscious and subconscious mind a belief that you won’t get well, and as long as the mind holds this negative belief, it becomes a self-fulfilling prophecy. If you believe you’ll never recover, you won’t.

The Moral Of This Story

After reading through the 3500+ case studies documented in the medical literature in the Spontaneous Remission Project, which was compiled by the Institute of Noetic Sciences, I now believe there’s no such thing as an incurable illness. If you or someone you love is suffering from a “chronic,” “incurable,” or “terminal” illness and you want to optimize the chance for spontaneous remission, you have to start by cleansing your mind of any negative beliefs that will sabotage your self-healing efforts. My upcoming book Mind Over Medicine: Scientific Proof That You Can Heal Yourself (which you can now pre-order at Amazon or Barnes and Noble!)  offers tips for how you can change your negative beliefs to positive ones in order to optimize your chances.

What Do You Believe?

Do you believe you’ll be on meds for the rest of your life? Are you resigned to the prognosis your doctor gave you? Or are you motivated to try to activate your body’s innate self-repair mechanisms by shifting your beliefs from negative ones to positive ones?

Tell us your thoughts in the comments.

With faith in your journey,

Lissa Rankin

Lissa Rankin, MD: Creator of the health and wellness communities and, author of Mind Over Medicine: Scientific Proof You Can Heal Yourself (Hay House, 2013), TEDx speaker, and Health Care Evolutionary. Join her newsletter list for free guidance on healing yourself, and check her out on Twitter and Facebook.



Tammy B.
Tammy B.6 years ago

Just as the bible teaches us that what one man considers a sin, to him is a sin. So therefore if I believe eating White bread will in time kill me, if I eat it I will die. So this goes even if a fake drug is administered to one, the fake also side effects can be all to real to the one taking the fake drug. Isn't this called mind over matter?

Richard T.
Richard T6 years ago


Eternal Gardener
Eternal Gardener6 years ago

They sure can!

Syd H.
Syd H6 years ago

For example, if you tell a patient treated with a placebo he might experience nausea, he’s likely to feel nauseous.

It is "nauseated" not nauseous. Nauseous is what someone is that causes others to become nauseated.

Otherwise it's great to showcase the idea of mind over matter. From a religious standpoint it is part of what Jesus was trying to teach us. We are all capable.

There's nothing greater than Faith (at least coupled with a very good, clean diet).

But this feels like a book advertisement. :(

nahia l.
nahia L6 years ago

I also think that "positive thinking", optimism and faith can help healing... but not all disease and illnesses are due to negative thoughts. What about babies with AIDS, young kids with leukemia or even animals who get those kinds of incurable illnesses? I don't think they worry about their health or thought about their death....most of them can't grasp the seriousness of their ailment or know of how much time they have to live and they still die.....

Marie W.
Marie W6 years ago

We have all heard of 'worrying yourself to death'.

Rachel R.
Rachel R6 years ago

This is such a tricky area. I think we need to discuss it so we can have more good studies of both the placebo and nocebo effect. However, we will never really be able to control what people think, or maybe even what we think. It's also, as Lissa has written about before, a tricky line between empowering people and blaming them. if the problem is your thoughts and your don't get well then it can be hard to see how that isn't ALSO your own fault. Which of course doesn't help.

Amber Beasley
Amber Beasley6 years ago

thanks. this is very true.

Pamela Tracy
Pamela Tracy6 years ago

Even if we have good thoughts others negative thoughts can harm us. Lets face it..the medium and the govts want to down American and Americans. So, how best to harm someone else ...think bad thoughts about them. That is unless you think you might be gotten back at by those that harm us. I never had bad thoughts ...I was a true Christian having non dirty compassion about people who were having trouble in their lives. When it was my turn to receive some thoughtful help only those who wanted to get themselves out of trouble sought me because I did not know of their issues so they wanted to hurt me by telling me their issues, like I was spoiled or something. I had my own problems. I had to keep myself up and decent because I was a 60's decent divorced woman. But, men in our world then and now wont get to heaven any faster by crapping on us women in thought or deed.

tiffany t.
tiffany t6 years ago

i agree with you about the mind being a powerful entity but what are your thoughts about Lou Gehrig's disease, Alzheimer's/ dementia, parainfluenza, influenza, respiratory syncytial viruses, and reoviruses. Rhinoviruses, Ebola, Polio, HIV/AIDS, yes there are people who have been genetically proven not to be able to be infected with HIV/AIDS and Polio is Africa and South Asia. Approximately 1,000–2,000 children are still paralyzed by polio each year, most of them in India. The list can go on and on, and I am not sure about giving people fake surgery is that legal? I am appreciative that you are trying to change the way patients are treated in medicine, don't get me wrong, but even the most positive person can die from cancer.