Psychological flexibility as a predictor of fear of happiness in young adults: the role of life satisfaction

Psychological flexibility is considered a central process within the framework of Acceptance and Commitment Therapy (ACT); however, its relationship with fear of happiness remains insufficiently understood. The present study aims to examine the associations between psychological flexibility, fear of happiness, and life satisfaction in young adults, and to investigate whether life satisfaction functions as a potential mediating mechanism in this relationship. In this context, the study seeks to evaluate whether fear of happiness can be explained through process-based regulatory mechanisms. A cross-sectional design was employed with a sample of 370 university students aged 19–26. Data were collected using the Acceptance and Action Questionnaire-II, the Fear of Happiness Scale, and the Satisfaction with Life Scale. A moderated mediation analysis was conducted using PROCESS Model 59 with 5,000 bootstrap samples. The results indicated that psychological flexibility was negatively associated with fear of happiness and positively associated with life satisfaction. Although life satisfaction was significantly related to both variables, the small magnitude of the indirect effect and the absence of a consistent indirect effect at the model level suggest that life satisfaction does not function as a strong mediating mechanism in this relationship. In addition, the index of moderated mediation was not statistically significant, indicating that the indirect effect did not differ reliably across groups. These findings suggest that psychological flexibility is directly associated with fear of happiness and that this relationship is relatively independent of global evaluations of life. From an ACT perspective, maladaptive responses to positive emotions appear to be more closely related to low psychological flexibility and associated experiential avoidance processes than to general cognitive evaluations of life circumstances. Overall, the results highlight the central role of process-based mechanisms in understanding fear of happiness and underscore the importance of enhancing psychological flexibility in interventions aimed at reducing maladaptive beliefs about positive emotional experiences.