Just-in-time adaptive interventions to improve positive emotions in daily life: a randomized controlled experience sampling study

Positive psychology interventions may improve mental health, especially when tailored to individuals’ needs and context. This randomized controlled study investigated the feasibility and effectiveness of just-in-time adaptive interventions (JITAIs) inspired by positive psychology principles. Students (N = 142) completed two experience sampling (ESM) periods of 15 days each. During the second period, participants who were randomly assigned to the intervention group (N = 72) received JITAIs. Mental health (i.e. well-being, anhedonia, depressive symptoms) was assessed before, after, and 3 months after the study. Although JITAIs were positively evaluated, they did not significantly impact momentary emotions or longer-term mental health. Qualitative analyses further showed that, while participants reported benefits from JITAIs, these interventions were not always considered necessary and introduced practical challenges. In conclusion, implementing JITAIs is feasible, but not consistently effective in improving mental health. Further research should investigate how to optimize just-in-time and adaptive delivery to better suit individual needs.