How External Cues and Treatment Expectations Influence Pain Perception Differently, Study Shows

Recent research highlights that our expectations about pain, shaped by external cues or verbal information from healthcare providers, can influence how much pain we experience, but through distinct neural mechanisms. Led by scientists from the National Institutes of Health and published in the Journal of Neuroscience, the study investigated how these different expectation sources impact pain perception.

The study involved 40 healthy volunteers subjected to painful heat stimuli while undergoing neuroimaging scans. Participants were conditioned to associate certain external cues with pain relief, and some received a placebo lotion suggesting pain reduction. Results demonstrated that external cues generally reduced perceived pain across all participants. However, only about half reported less pain when a placebo lotion was introduced, indicating that the expectation built solely through external cues has a more consistent analgesic effect.

Neuroimaging data revealed that external cues and placebo treatments activate different brain regions. External cues primarily influenced brain areas associated with pain processing, directly modulating pain perception. In contrast, expectations related to placebo treatments engaged evaluative and cognitive regions, affecting pain indirectly through psychological mechanisms.

The findings suggest that clinicians should be mindful about how they communicate treatment expectations. Verbal cues indicating potential pain relief can have a genuine and consistent impact on patient comfort. Conversely, warnings or negative information about pain might influence perception differently.

As Lauren Atlas, one of the lead researchers, explained, "If a doctor says, 'This is going to hurt,' that creates a cue that can intensify pain. When they say, 'This treatment will relieve your pain,' it sets a different expectation with potentially beneficial effects. Understanding these mechanisms can help improve patient care."

This research underscores the importance of framing communication positively in healthcare to optimize pain management strategies.

For more details, see the full study: Isolating Brain Mechanisms of Expectancy Effects on Pain: Cue-Based Stimulus Expectancies Versus Placebo-Based Treatment Expectancies.