Table 1.

Eligibility criteria

Inclusion criteria

Exclusion criteria

Provision of written informed consent Aged 18 years old or above Using opioids for chronic non-malignant pain Using strong opioids for at least 3 months Using strong opioids on most days in the preceding month Fluent in written and spoken English Able to attend group sessions Willingness for GP to be informed of participation

Regular use of injected opioid drugs Chronic headache as the dominant painful disorder Serious mental health problems that preclude participation in a group intervention Previous entry or randomisation in the present trial Participation in a clinical trial of an investigational medicinal product in the last 90 days Pregnant at time of eligibility assessment, or actively trying to become pregnant.* People receiving strong opioid for the management of pain due to active malignant disease

*Added as exclusion criteria from 15 November 2018.

GP, general practitioner.