We have long understood that patient expectations influence clinical outcomes. A confident explanation, a reassuring tone or an optimistic outlook can positively transform the patient experience, producing a placebo effect. But the latest neuroscience research has revealed a surprising finding: Negative expectations produce nocebo effects that are not only more powerful than placebo effects, but also more persistent.
These findings are not just theoretical. They have a practical impact on everyday practice.
A Tale of Two Chiropractors
Several years ago, we hired two chiropractors for one of our clinics. Their backgrounds were very similar. Both graduated from the same chiropractic college, practiced for about four years before joining us, and used the same diversified techniques. Each completed our six-month onboarding program, designed to integrate associates into our protocols and clinical benchmarks, and both succeeded.
Yet within a year, their patient results began to diverge. Dr. A’s patients consistently reported larger improvements in both pain relief and function. Dr. B’s patients improved as well, but not to the same degree.
Our clinic director shadowed both associates to find an explanation. The difference was not attributable to each doctor’s techniques or protocols. It was related to their communication styles. Dr. A used encouraging, optimistic talking points, reinforcing progress and setting positive expectations. Dr. B, while technically proficient, offered little in the way of uplifting or forward-looking language.
The lesson was unmistakable: Words matter. Dr. A was harnessing the placebo effect through positive framing, while Dr. B was leaving patients vulnerable to the subtle but powerful impact of negative expectations – the nocebo effect.
What the Science Shows
A recent study compared placebo and nocebo effects in 104 healthy volunteers. Participants were exposed to short bursts of experimental heat pain.1 Verbal suggestions shaped their expectations: some were told the stimulus would feel better (placebo), others that it would feel worse (nocebo). Both effects were measurable, but nocebo responses were stronger and more enduring.
On average, participants rated their pain 11% higher under negative expectations than in a neutral control condition. Even a week later, nocebo effects remained significantly stronger than placebo effects. By contrast, positive expectations (placebo) reduced pain by about 4%, showing that while optimism helps, negative expectations are nearly three times more powerful in shaping pain perception.
Evolutionary psychology offers an explanation. Humans are hard-wired to prioritize potential threats. This “better safe than sorry” strategy once protected survival, but it now makes us especially susceptible to negative suggestions. In clinical care, this means patients often respond more powerfully to words of caution or doubt than to words of reassurance.
The Power and Risk of Communication
Our patients often arrive anxious, discouraged or frustrated by chronic pain. What we say in those first moments (and how we say it) can tip the balance toward healing or toward heightened distress.
Practical Strategies for Chiropractors
- Explain Clearly: Patients need to know not only what you’re doing, but also why. Set clear expectations for outcomes and timelines.
- Frame Progress Positively: Emphasize improvements and resilience, even when recovery is gradual.
- Avoid Catastrophic Language: Replace alarming phrases with constructive reassurance.
- Support Shared Decision-Making: Patients who feel involved in choosing their care tend to trust the process more, which strengthens positive expectancy effects.
A Call to Action
The story of Dr. A and Dr. B illustrates what the science now confirms: Communication is not a side note to care; it is a core component of outcomes. Nocebo effects are stronger, longer-lasting and easier to trigger than placebo effects. But by consciously shaping patient expectations, chiropractors can reduce harm, amplify healing and set a new standard for patient-centered care.
In the end, technique matters, but so do words. The most effective chiropractors adjust both the spine and the story their patients carry into the healing process. The key is to help patients by clarifying expectations and reducing anxiety.
Reference
- Kunkel A, Schmidt K, Hartmann H, et al. Nocebo effects are stronger and more persistent than placebo effects in healthy individuals. eLife, 2025;14:RP105753.
