Background & Aims

Chronic pain is frequently refractory to pharmacological and interventional therapies. Hence, interest is growing towards mechanisms, which might participate in disease maintenance, including a maladaptive stress response, poor sleep quality, or ineffective coping strategies. Medical hypnosis, a complementary non-pharmacological approach, might address these maintaining factors [1], and has shown clinical efficacy in chronic pain [2].
The literature has been calling for direct comparisons between hypnosis and germane processes, including the recruitment of the placebo effect [3]. Open label placebo (OLP i.e., the prescription of a pill without active pharmacological substance, associated with truthful information regarding the psychobiological mechanisms) has shown promising results in different chronic pain conditions [4]. Here, we proposed to compare these two mind-body techniques involving expectations and mindset shifts, to as control group receiving treatment as usual (TAU).

Methods

This monocentric RCT enrolled patients suffering from peripheral neuropathic pain, randomized 1:1:1 to OLP, hypnosis or TAU for 8 weeks. Hypnosis consisted in 6 individual semi-scripted session and self-hypnosis audios to be used daily. In the OLP group, patients were provided with the psychobiological rationale and a bottle of placebo capsules explicitly labelled as “placebo” and instructed to take 2 capsules twice a day. Before randomization, beliefs regarding hypnosis and OLP and expectations were evaluated using VASs from “not effective at all=0” to “very Much=10”. Patients rated their treatment preference on a VAS (OLP=0; hypnosis=10). Questionnaires were filled before and after the treatment: Brief Pain Inventory (BPI), anxiety and depression (HADS), pain catastrophism (PSC); Insomnia Severity (ISI), pain coping strategies, resilience (BRS). After 8weeks, patients evaluated their satisfaction on a VAS and overall improvement using the Global Impression of Change (PGIC).

Results

The sample consists in 72 patients (39 women, aged 46.6 ± 14.1) suffering from moderate to severe pain at baseline (BPIseverity:4.8 ± 1.8; BPIinterference: 4.5 ± 2.2). The patients presented high beliefs and expectations for both treatments, with significantly higher scores for hypnosis than OLP (beliefs: 7.3±2.0 vs. 6.5±2.2, t(71)=2.8, p=0.01; expectations: 7.2 ± 2.0 vs. 6.1 ± 2.5; t(71)=4.3, p<0.001). Their mean preference was in favor of hypnosis (7.3 ±3.0) with only 11 patients (15%) preferring OLP. The preliminary analysis revealed a significant treatment effect on satisfaction (F(2,52)=4.2, p=0.02) and PGIC (H(2)=9.4, p=0.001) with patients in the hypnosis group feeling more satisfied and overall improved than in TAU and OLP groups. There was no treatment effect on the BPI and HADS scores. Further analyses will be presented regarding treatment effects on stress response parameters, measures of sleep, and coping strategies.

Conclusions

An 8-week treatment of Hypnosis demonstrated a significant positive effect in patients suffering from neuropathic pain, at least on subjective outcomes, compared to treatment as usual and OLP. The OLP arm did not show positive treatment effects. This is one of the first OLP studies with an active comparator. Interestingly, patients preferred the other therapeutic option. This might have negatively impacted the effects of the OLP, compared to prior studies, where it was the only active treatment. Further analyses will allow to dissect potential mediators of the observed results, including treatment preference, expectations, measures of the stress response, sleep quality, coping strategies, or personality.

References

[1] Bushnell et al., 2013 ; Nat Rev Neurosci
[2] Langlois et al., 2022 ; Neurosci Biobehav Rev.
[3] Terhune et al., 2017 ; Neurosci Biobehav Rev
[4] von Wernsdorff et al., 2021; Sci Rep

Presenting Author

Aurore Fernandez

Poster Authors

Aurore Fernandez

PhD

CHUV

Lead Author

Marc Suter

Lausanne University Hospital

Lead Author

Irving Kirsch

Pr

Program in Placebo Studies; Beth Israel Deaconess Medical Center / Harvard medical school

Lead Author

Chantal Berna

Pr

Center for complementary and integrative medicine, Lausanne University Hospital

Lead Author

Topics

  • Treatment/Management: Complementary and Alternative therapies