Negative language use of the physiotherapist in low back pain education impacts anxiety and illness beliefs: A randomised controlled trial in healthy respondents

Objective: This study aimed to determine the effect of physiotherapists' negative language use on nocebo effects of state anxiety and illness beliefs.Methods: A web-based randomised controlled trial included adults without recent musculoskeletal pain. The intervention was a short educational video about low back pain using negative language (nocebo condition: n = 87) versus a video using neutral or positive language (control condition: n = 82). State anxiety was assessed using the State-Trait Anxiety Inventory. Illness beliefs were assessed using the Illness Perception Questionnaire.Results: Nocebo and control groups differed in outcome measures (MANOVA Pillai's trace = 0.22, F = 4.98; df = (9,159), p < 0.001). Post-hoc analyses showed a medium to large effect for the nocebo condition on anxiety (d = 0.71, 95% CI 0.4 -1.0). The nocebo group also had higher scores in three illness beliefs: beliefs on timeline (d = 0.45, 95% CI 0.14 - 0.75), treatment control (d = 0.43, 95% CI 0.12 - 0.74) and concern (d = 0.47, 95% CI 0.16 - 0.78).Conclusion: Physiotherapists' use of negative language contributes directly to a higher state anxiety and illness beliefs that can trigger the nocebo effects in the recipientPractice implications: Negative language use should be avoided.

Automated summary

This study aimed to determine the effect of physiotherapists' negative language use on nocebo effects of state anxiety and illness beliefs. The results showed that the group exposed to negative language had higher levels of anxiety and illness beliefs, suggesting that negative language should be avoided.