The Effectiveness of Group Training Based on Unified Transdiagnostic Therapy on Emotion Regulation and Smartphone Addiction in Adolescent Girls: The Moderating Role of Maternal Emotion Regulation

Abstract

Introduction and Aim: Adolescence is a critical developmental period characterized by substantial emotional and social changes, and deficits in emotion regulation may increase vulnerability to maladaptive behaviors such as smartphone addiction. The present study aimed to investigate the effectiveness of group training based on the Unified Transdiagnostic Treatment on emotion regulation and smartphone addiction in adolescent girls while considering the moderating role of mothers’ emotion regulation.

Methodology: This study employed a quasi-experimental pretest–posttest multi-group design with a control group and a two-month follow-up. The statistical population consisted of 10th- and 11th-grade female students enrolled in vocational high schools (Work and Knowledge track) in Arak, Iran, and their mothers in 2024. The sample included 77 adolescent girls and 52 mothers who were selected through purposive sampling and assigned to three groups: an experimental group with maternal training, an experimental group without maternal training, and a control group. The research instruments included the Difficulties in Emotion Regulation Scale (DERS) and the Smartphone Addiction Scale–Short Version (SAS-SV). The intervention was administered in 12 weekly 60-minute sessions for adolescents and 5 weekly 90-minute sessions for mothers. Data were analyzed using multivariate and univariate analysis of covariance, repeated measures ANOVA, and Bonferroni post hoc tests.

Findings: The results of multivariate analysis of covariance indicated that the intervention had a significant effect on the combined variables of emotion regulation and smartphone addiction (p<0.001). Univariate analyses further demonstrated that both experimental groups showed significant reductions in emotion regulation difficulties and smartphone addiction compared with the control group. Moreover, maternal emotion regulation played a significant moderating role in the effectiveness of the intervention, with greater improvement observed in the group that received maternal training in addition to adolescent intervention. Repeated measures ANOVA also revealed that the intervention effects remained stable at the two-month follow-up, as no significant differences were found between posttest and follow-up scores.

Conclusion: The findings suggest that group training based on the Unified Transdiagnostic Treatment is an effective approach for improving emotion regulation and reducing smartphone addiction among adolescent girls. Furthermore, involving mothers and enhancing their emotion regulation skills can strengthen the effectiveness of the intervention, highlighting the importance of family-centered approaches in addressing adolescents’ emotional and behavioral difficulties.