The INternet ThERapy for deprESsion Trial (INTEREST): protocol for a patient-preference, randomised controlled feasibility trial comparing iACT, iCBT and attention control among individuals with comorbid chronic pain and depression

IntroductionApproximately one-third of adults with chronic pain also report clinically relevant levels of depression. Internet-delivered psychological therapies such as Cognitive Behavioural Therapy (iCBT) and Acceptance and Commitment Therapy (iACT) have been developed to overcome barriers of access to services and ensure the timely delivery of care. The objective of this trial is to collect data on feasibility, acceptability and range of probable effect sizes for iCBT and iACT interventions tailored towards the treatment of depression and chronic pain using a randomised controlled patient-preference design.Methods and analysisCommunity dwelling adults with chronic non-cancer pain (CNCP) and major depression will be recruited from pain clinics and primary care providers in Newfoundland and Labrador, Canada. The study is a randomised controlled patient-preference trial. Eligible patients will be randomly assigned to a ‘preference’ or ‘no-preference’ arm during the first step of randomisation and to intervention or control in the second step of randomisation. Two interventions (ie, iCBT or iACT) will be evaluated relative to attention control. iCBT and iACT involve the completion of 7-weekly online modules augmented with one session of motivational enhancement and weekly therapy sessions. Primary outcomes include (1) feasibility and acceptability parameters and (2) change in symptoms of depression. Secondary outcomes include pain, physical function, emotional function and quality of life. We will recruit 60 participants and examine the range of effect sizes obtained from the trial but will not conduct significance testing as per recommendations for behavioural trial development.Ethics and disseminationEthics was approved by the provincial Health Research Ethics Board. Dissemination of results will be published in a peer-reviewed academic journal and presented at scientific conferences.Trial registration numberNCT04009135.