Abstract
Background
Well-being websites and apps are increasingly available. Given their scalability and accessibility, online interventions are generally considered a promising avenue to promote public subjective well-being. However, the success of online interventions in public mental health promotion depends on widespread acceptance and sustained engagement. This study explores the feasibility, acceptability, and preliminary effectiveness of an unguided online intervention for non-clinical Belgian adults.Methods
In this quasi-experimental study, 208 participants were assigned to either the intervention group (n = 68) or control group (n = 140) based on their own preferences. The online intervention allowed participants to choose from a range of activities, including mindfulness, breathing exercises, walking, and cycling. Data were collected at baseline and after 8 months. Feasibility was assessed via uptake, attrition, and engagement. The assessment of acceptability was based on the Theoretical Framework of Acceptability. Inverse probability of treatment weighting was performed to balance the treatment arms and weighted linear mixed models were used to evaluate improvements in terms of subjective well-being, peace of mind, and meaningfulness.Results
Uptake of the intervention was low (32.7%) and dropout in the intervention group was substantial (63.2%). A major barrier to uptake was competing commitments. Non-completers had higher baseline negative affect (M = 2.54, SD = 0.56) than completers (M = 2.16, SD = 0.61). Among the completers, 81.3% found the intervention acceptable, yet 44.0% reported virtually no engagement. The intervention group showed statistically significant improvements in meaningfulness compared to the control group (β = 0.55, 95% CI [0,11; 0,99], p Conclusion
Low uptake, engagement, and adherence remain major obstacles to the success of unguided online interventions. Key lessons learned from this study highlight the need to address barriers to uptake during the design phase, implement strategies to sustain user motivation and engagement, and acknowledge that digital well-being interventions may not adequately support those who need it most.