Psychosocial stress is a major public health concern, contributing to significant suffering and costs to society. There is a lack of effective interventions that could be offered at an early stage to people who need to reduce their stress in life. Recent advances in psychology have provided evidence-based exercises suitable for testing in an entirely digital intervention. This study aims to estimate the effectiveness of a 12-week digital course in mindfulness- and acceptance-based stress reduction.

The effectiveness of the 12-week digital course will be estimated in a parallel-groups randomised controlled trial, in which the control group will receive referrals to self-studies on mental health information found online. The study population will be individuals 15 or older, seeking help online for stress and who have access to a mobile phone. Employing a Bayesian sequential design, the primary outcome will be monitored monthly, after the 6-month follow-up, to calculate target criteria for when to stop recruiting. Perceived stress (Cohen’s 10-item version) will be the primary outcome, with estimands of interest being differences between groups at 3 (immediate), 6 (prolonged) and 12 months (maintained). Mediation analysis will reveal if differences between groups are mediated by acquired equanimity. Effectiveness will be analysed with Bayesian regression models, and mediation will be analysed by using a causal inference framework.

The research was approved by the Swedish Ethical Review Authority on 2024-05-07 (2024-01974-01). The study will reach out to a vulnerable population, and participation may displace efforts to seek professional help. We have built-in automatic advice to seek additional help for participants scoring high on the depression scale at baseline, before allocation to study groups. The findings from this study will be submitted to peer-reviewed journals and presented at relevant national and international meetings.

ISRCTN39222610.

Alcohol consumption that damages health remains highly prevalent in Sweden despite macrolevel intervention measures such as availability, restrictions and taxation. As understanding of behaviour change develops, there may be an opportunity to enhance individual level interventions by targeting personal dimensions of behaviour, such as underlying motives for drinking alcohol and readiness to change behaviour. This protocol describes a randomised controlled trial aimed at estimating the effectiveness of an intervention tailored to motives and readiness to change.

A three-arm, parallel groups, randomised controlled trial will be used to estimate the effects of a motives and readiness to change tailored intervention. We will use a Bayesian sequential design to decide when to stop recruitment, with target criteria for benefit, harm and futility. Recruitment will be completed via web adverts and social media. Inclusion criteria are being aged 18 or older, having access to a mobile phone and being classified as a risky drinker. Participants allocated to the two intervention groups will receive either a personalised digital intervention or an intervention with enhanced tailoring for motives and readiness to change. The personalised intervention consists of weekly screening, personalised feedback and tools for planning behaviour. The enhanced tailored version will follow the same logic but will contain materials tailored for individuals’ drinking motives and readiness to change. The control group will be redirected to two national websites with information about alcohol and health. Outcome measures are weekly alcohol consumption and monthly heavy drinking episodes, which will be contrasted with regression models and estimated using Bayesian inference.

Ethical approval was obtained from the Swedish Ethical Review Authority on 16 April 2024, (Dnr 2024-01630-01). The results of the study will be disseminated in academic journals and research conferences.

The trial was preregistered in the ISRCTN Registry on 12 June 2024 (ISRCTN87600318).