This randomized-controlled trial (RCT) will evaluate the effectiveness of a pain psychology intervention -- consisting of a hybrid of acceptance and commitment therapy (ACT) and clinical hypnosis intervention -- in reducing opioid consumption after major surgery. Consenting patients undergoing oncology surgeries at Toronto General Hospital (TGH) will be randomly assigned to one of two groups: (1) standard care or (2) standard care plus an ACT/clinical hypnosis intervention for pain management. The hypnosis intervention will be delivered via one session with a psychotherapist prior to surgery, one session with a psychotherapist after surgery, and the provision of audio recordings to guide patients in practicing self-hypnosis. The pain psychology intervention is targeted at reducing pain, as well as pain-related anxiety, distress, sleep disturbance, and functional impairment. The primary goal of the pain psychology intervention is to help patients to feel more comfortable while using less opioid medication in the week after surgery.

Hypnosis is one of the oldest strategies for the management of pain; however, interest in hypnosis as a pain management strategy has ebbed and flowed over time. Given the current concern over opioid use for pain management, non-pharmacological pain management options, such as clinical hypnosis, are being revisited. In addition, over the past twenty years, there has been a new wave of scientific investigation into the efficacy of hypnosis for acute and chronic pain. As a result of this body of evidence for the efficacy of clinical hypnosis for pain management, the American Psychological Association has recommended that clinical hypnosis be included as part of standard care for pain relief, unless an individual indicates a strong aversion to it.

Previous research has investigated the utility of clinical hypnosis for pain management in the perioperative context. Surgical patients who received adjunct hypnosis treatment had better outcomes (e.g., less pain, better mood, and less medication use) than 89% of patients who received treatment as usual, as evidenced by large effect sizes across 1624 patients from randomized and non-randomized controlled trials. A more recent meta-analysis demonstrated small to medium effects in favor of hypnosis on various post-surgical outcomes (e.g., pain, emotional distress, medication consumption, and post-surgical recovery), across 2597 patients in randomized controlled trials. Although these meta-analyses have demonstrated an association between the implementation of hypnosis interventions and an overall reduction in medication consumption, previous investigations have rarely focused specifically on reduced use of opioid medication, which is important in the context of current concerns about opioid overuse.

Furthermore, meta-analyses have indicated that dysregulation of the parasympathetic nervous system is associated with the development of chronic pain, leaving sufferers unable to regulate stress, recovery, and relaxation processes. The investigators hypothesize that the relaxation associated with the clinical hypnosis intervention will lead to activation of the parasympathetic nervous system and, accordingly, greater heart rate variability. Therefore, the investigators hypothesize that patients who are randomized to the clinical hypnosis treatment will not only use less opioid medication in the week after surgery, but will also demonstrate greater heart rate variability at one month post-surgery, which is thought to protect against the development of long-term pain.

The study's goal is to provide patients with a range of strategies that will be most helpful and efficacious in reducing suffering during the pre- and post-operative periods. A secondary goal is to deliver as much therapeutic content as possible through audio recordings in order to create a psychological intervention that requires less face-to-face contact between clinician and patient, but provides more support (e.g., patients can listen to the recordings at bedtime when the clinician would not be available on a daily basis). The use of audio recordings will conserve staffing resources, while at the same time allowing for the dissemination of pain psychology tools to more patients. Therefore, in the current study, the study aims to test the feasibility and efficacy of this approach, termed ACT-Informed Clinical Hypnosis.

Inclusion Criteria:

• Age: 18-80
• Scheduled for surgical oncology procedure (i.e., thoracic, gastrointestinal, gynecologic oncology, urologic, head and neck or breast cancer surgery)

Exclusion Criteria:

• Patients with limited comprehension of English who would not be able to understand the verbal instructions for clinical hypnosis
• Patients with a known history of serious mental illness (e.g., schizophrenia and/or current PTSD)
• Patients with cognitive deficits due to dementia whose comprehension may limit benefit

Random assignment to group will take place after baseline assessment. Patients who are randomly assigned to the clinical hypnosis group will immediately undergo their first in-person hypnosis session focused on preparing for surgery. Masking is not employed as patients will know if they are randomized to the intervention arm.