The Placebo Effect on Pain Perception and Healing

The placebo effect is a general term that describes the physiological effects of believing that we’re going to feel better or heal from a condition.

The placebo effect has long been discounted in Western medicine—when placebos work, we’re just imagining that we’re getting better, we’re not actually getting better.

Until fairly recently, there hasn’t been much evidence to explain the placebo effect. Luckily, that’s changing, and I’ve been reading a great deal about it. Unfortunately, the term “placebo effect” has the strong connotation of being imaginary or inconsequential. In order for people to accept the science of how our thoughts affect our health—both our function and our physical structure at a cellular level—we may need to use a new term to describe how this mechanism works.

Increasing evidence explains the placebo effect

It’s hard to ignore the placebo effect when in clinical drug trials, the placebo group often reports similar or equal improvement as the treatment group. But since no one stands to make money off of placebos, relatively few studies on their efficacy have been done.

When reading stories of how people recover naturally from cancer, Parkinson’s Disease, multiple sclerosis and other autoimmune conditions, it can be difficult to understand how or why they recovered. People report using such varied approaches—including herbal medicine, TMJ adjustments, Qigong, and sound therapy, to name a few—that it’s hard to identify a common denominator.

The common denominator is belief: The belief that you will get better. Yes, you absolutely need to have certain things in place such as a balanced diet, a healthy stress level, and enough exercise and sleep. You must address potential infections, allergens, and toxins. But if you don’t believe that you’re going to get better, you probably won’t.

There’s been enough research on the effect of positive thinking on pain perception that it’s now accepted that a positive attitude can reduce your pain, and vice versa—we’ll talk about this in the next two sections. But new research showing the effect of positive thinking on our immune system function should lead to wider acceptance of how our thoughts affect our health.

A 2016 study showed that when we believe we’re going to get better, our brain’s mesolimbic reward system is activated, triggering the release of dopamine. Researchers focused on the ventral tegmental area (a brain area that plays a key role in regulating dopamine) because stimulating this area improves the antibacterial activity of the immune system. The study found that when the brain’s reward system was stimulated, immune cells destroyed twice as many bacteria.

In 2018, the same group of researchers released a study showing that stimulating the brain’s reward system shrinks cancerous tumors in mice.

Excited doesn’t begin to describe how I feel about the fact that we’re beginning to get some scientific evidence about how our thoughts affect our health. It seems that Western medicine is finally coming around to the reality that drugs are rarely the best solution for chronic health conditions, and that we have an incredible ability to heal ourselves.

If you want to learn more about this topic, here are some books (and one documentary) that I enjoyed:

Heal (available for free with Netflix subscription)
The Biology of Belief by Bruce Lipton
The Intention Experiment by Lynne McTaggart
The Telomere Effect by Elizabeth Blackburn and Elissa Epel
Fighting Parkinson’s…and Winning by Howard Shifke
Beyond Terminal by Chris Collins

The placebo effect on pain perception

Endogenous opioids are substances produced by our central nervous system and pituitary gland. They function both as hormones and neuromodulators, modifying the behavior of other neurotransmitters. The most famous type of endogenous opioid are endorphins (a contraction of “endogenous,” meaning naturally occurring, and “morphine”).

Endogenous opioids act in numerous areas of the brain, spinal cord, and peripheral nerves to dull pain and produce a sense of euphoria. Our opioid system regulates our mesolimbic reward system, so when our reward system is stimulated, endogenous opioids are released.

The placebo effect was linked to the release of opioids back in 1978, when a study examined the placebo effect in dental postoperative pain. When patients were given naloxone (a drug that blocks opioid receptors in the nervous system), the placebos stopped relieving their pain.

So, when we believe our pain is going to be relieved, our reward system is stimulated, endogenous opioids are released, and our pain actually is relieved. This is called placebo analgesia. It’s real, and it’s awesome, in the true sense of the word.

The nocebo effect on pain perception

So now we know that if you expect your pain to get better, it probably will. But the opposite is also true: If you expect your pain to continue or get worse, it probably will. When you’re in pain, it can be difficult to believe you’ll get better. But finding a way to have a positive attitude is one of the best things you can do for yourself.

The increase in pain from negative expectations is called nocebo hyperalgesia, and research has shown how this effect occurs at a neurobiological level. Brain-imaging studies show increased activation of a pain pathway known as the medial pain system when subjects expect that a stimulus will be painful. So it’s important to understand that having a negative expectation doesn’t just mean that you’ll report your pain as being worse—it means you’ll actually experience more pain.

Researchers found they can predict which surgical patients will experience greater postoperative pain based on presurgical assessment using the Pain Catastrophizing Scale. The scale measures how fixated the patients are on their pain, to what extent they magnify their pain and expect that it will get worse, and their feelings of helplessness. The more patients catastrophize about their pain before the surgery, the more pain they experience afterward.

Changing your habitual thought patterns

Over the course of our lives, we develop habitual ways of thinking just as we develop habitual ways of standing and moving. It’s easy for us to get stuck in old thought patterns. It can be difficult to get objective feedback on how we think and even more difficult to listen to the feedback rationally, learn from it, and change. But as a friend of mine says, “Don’t believe everything you think.” Just because you think something doesn’t mean it’s true.

We are the only beings on the planet who have the ability to change our thought patterns and choose how we interpret and react to situations. When your thought patterns and reactions have become habitual, it may not feel like you can change them. But remember that your nervous system is plastic—so with practice and repetition, you can retrain your learned thought patterns and reactions.

Our habits make us comfortable, and changing our deeply learned patterns takes effort and willpower. If you find yourself thinking negatively about your pain, stop yourself and try to think about your situation in the opposite way. Instead of telling yourself, “My back is just going to get worse and worse. I’ll never be able to hike again,” practice thinking, “My back is going to get better! This pain is going to go away and I’ll be so excited to go hiking again!”

With practice, positive thinking will become easier and even habitual. And remember, positive thinking won’t just improve your attitude—it will actually reduce your experience of pain on a neurobiological level.


1. Ben-Shaanan, T.L., et al. “Activation of the reward system boosts innate and adaptive immunity.” Nature Medicine 22, (2016): 940–944.

2. Ben-Shaanan, T.L., et al. “Modulation of anti-tumor immunity by the brain’s reward system.”
Nature Communications 9, (2018): Article 2723.

3. Colloca, L., and F. Benedetti. “Nocebo Hyperalgesia: How Anxiety Is Turned into Pain.” Current Opinion in Anaesthesiology 20, no. 5 (October 2007): 435–439.

4. De Craen, A.J., et al. “Placebos and Placebo Effects in Medicine: Historical Overview.” Journal of the Royal Society of Medicine 92, no. 10 (October 1999): 511–515.

5. Kong, J., et al. “A Functional Magnetic Resonance Imaging Study on the Neural Mechanisms of Hyperalgesic Nocebo Effect.” Journal of Neuroscience 28, no. 49 (December 3, 2008): 13,354–13,362.

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7. Valance, A.K. “Something Out of Nothing: The Placebo Effect.” Advances in Psychiatric Treatment 12 (2006): 287–296.