Lessons learned from an unguided online well-being intervention for the general public

Abstract Background Well-being websites and apps are increasingly available. Given their scalability and accessibility, online interventions are considered a promising avenue to promote public well-being. However, their public mental health impact depends on broad acceptance and sustained engagement. This study examines the feasibility, acceptability, and preliminary effectiveness of an unguided online intervention for the general public. Methods In this quasi-experimental study, 208 adults were assigned to the intervention group (n = 68) or control group (n = 140) based on their preferences. Intervention participants could choose from several 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. Acceptability was evaluated with the Theoretical Framework of Acceptability. To balance baseline differences, inverse probability weighting was applied. Weighted linear mixed models evaluated changes in life evaluation, positive affect, negative affect, peace of mind, and meaningfulness. Results Uptake was low (32.7%) and dropout in the intervention group was high (63.2%). A key barrier to uptake was competing commitments. Within the intervention group, non-completers had higher baseline negative affect (M = 2.54, SD = 0.56) than completers (M = 2.16, SD = 0.61). Among completers, 81.3% found the intervention acceptable, yet 44.0% reported almost no engagement. The intervention group showed significant improvements in meaningfulness (β = 0.55, 95% CI = [0,11; 0,99], p = 0.015) but not in other outcomes. Conclusions Low uptake, engagement, and adherence remain obstacles to digital well-being promotion. Addressing barriers to uptake and implementing strategies to sustain engagement are essential to ensure public health impact. Moreover, digital well-being interventions may not adequately support those most in need and risk perpetuating well-being disparities. Key messages • Low uptake, engagement, and adherence jeopardize digital tools’ potential to promote well-being among the general public. • Digital well-being tools should be inclusive and suitable for individuals with low levels of well-being.