The effect and mechanism of acceptance and commitment therapy for young adults’ appearance-based rejection sensitivity and social comparison based on appearances: A randomized controlled trial

This study tested the effect and mechanism of acceptance and commitment therapy (ACT) on young adults’ appearance-based rejection sensitivity (ARS) and social comparison based on appearance (SCBA). A sample of 190 university students (Mage = 18.35, SD = 0.78; 56.62% female) was randomly assigned to either the ACT group (n = 94) or an active control group (n = 96), which focused on interpersonal discussions about experiences of appearance-based rejection. Participants completed six weekly group interventions, as well as three surveys: a baseline assessment before the intervention (T1), a post-test immediately after the intervention (T2), and a 3-month follow-up (T3). Clinically significant decreases in ARS and SCBA were observed in the ACT group from baseline to both the post-test and follow-up. Comparisons at each phase indicated that the ACT group outperformed the control group in reducing ARS and SCBA, as well as in improving psychological inflexibility and cognitive fusion. Furthermore, the parallel mediation models supported the mediating roles of psychological inflexibility and cognitive fusion between the ACTintervention and ARS /SCBA. These findings suggest that ACT is effective in reducing ARS and SCBA by improving psychological inflexibility and cognitive fusion. Future research should further explore the effects and mechanisms of ACT on ARS and its related constructs using diversified samples and multiple long-term follow-ups.