Comparing the clinical- and cost-effectiveness of an internet-delivered Acceptance and Commitment Therapy (ACT) intervention with a waiting list control among adults with chronic pain

INTERVENTION: The participants will be randomly allocated to one of two conditions: 1. ACT internet‐delivered psychological intervention Eight sessions over an 8‐week period. Delivered via the interactive online platform Lifeguide, consisting of information, homework assignments, relevant metaphors and mindfulness exercises. The participants will be reminded to complete each session weekly via a prompt to log on dispatched through the online delivery platform. Participants will also receive three phone calls from a member of the research team throughout the duration of the intervention, after their completion of sessions one, three and seven, respectively. 2. Waiting list control condition Participants will not receive the internet‐delivered ACT intervention at that time. The participants will be contacted by the post‐doctoral researcher to explain that they have been allocated to the waiting list control group, at which time the participants will be given an opportunity to ask questions regarding the trial. The waiting list control group will be offered the opportunity to use the online ACT intervention after the 6‐month follow‐up assessment. CONDITION: People with chronic pain ; Signs and Symptoms PRIMARY OUTCOME: Pain intensity and pain‐related functional interference: Brief Pain Inventory (BPI) ‐ Short form; ; People in both groups will be assessed pre‐treatment, post‐treatment (or after 8 weeks for the controls) and there will be a 6‐month follow‐up for both groups SECONDARY OUTCOME: 1. Depression: Beck Depression Inventory (BDI); 2. Pain‐related anxiety: Pain Anxiety Symptoms Scale‐20 (PASS‐20); 3. Patient Global Impression of Change: Patient Global Impression of Change scale (PGIC); 4. Acceptance of chronic pain: Chronic Pain Acceptance Questionnaire‐8 (CPAQ‐8); 5. Health‐related quality of life: EQ‐5D; 6. Health care usage: Client Service Receipt Inventory (CSRI); ; All secondary outcomes will be assessed at pre‐intervention, post‐intervention (or after 8 weeks for the control group) and at 6‐month follow‐up. INCLUSION CRITERIA: 1. Aged 18 years or over 2. The presence of pain for at least three months duration 3. Pain has been assessed by a general practitioner or specialist within the last three months 4. Resident of Ireland 5. Regular access to a computer and to the internet 6. Adequate English language ability