The Role of Psychological Flexibility and Emotion Regulation in the Relationship Between Smartphone Addiction and Psychological Wellbeing in Adolescents: Three-Wave Longitudinal Serial Mediation Study

Background When the increasing prevalence of Smartphone Addiction (SA) and its potential negative effects on mental health among adolescents are taken into consideration, an in-depth investigation of the relationship between SA and Psychological Well-being (PW) is of critical importance. Therefore, using a three-wave longitudinal research design, this study aimed to examine the serial mediation role of Psychological Flexibility (PF) and Emotion Regulation (ER) in the relationship between SA and PW. To our knowledge, this is the first study to examine SA, PF, ER, and PW relationships and mediating mechanisms in an adolescent sample using a longitudinal design. Methods The study included 448 adolescents (49.8% female and 50.2% male; Range _age =15–19, M _age =16.76, SD _age =1.12) who responded to the questionnaires in three waves. Participating adolescents responded to a 50-item questionnaire consisting of the Smartphone Addiction Scale-Short Version (SAS-SV), the Five-Dimensional Well-Being Scale for Adolescents (EPOCH), the Multidimensional Psychological Flexibility Inventory Short Form (MPFI-SF), and the Regulation of Emotions Questionnaire (REQ). The questionnaires were filled in using pen and paper in a classroom environment under the supervision of the teacher and the researcher. Results Compared to those who used their smartphones for 0–2 hours and 2–4 hours, adolescents who reported to use their smartphones for more than four hours daily were found to have higher SA scores and lower PW, ER, and PF scores across all three time points (T1, T2, and T3). The findings indicated that SA at T1 negatively predicted PW at T3 (β= -0.34, p < .001), PF at T2 (β= -0.39, p < .001), and ER at T2 (β= -0.23, p < .001). On the other hand, PF at T2 positively predicted ER at T2 (β = 0.17, p < .001) and PW at T3 (β = 0.40, p < .001), and ER at T2 positively predicted PW at T3 (β = 0.73, p < .001). Besides, PF at T2 (β= -0.15, SE = 0.03, 95% CI = [-0.2036, -0.1053]) and ER at T2 (β= -0.17, SE = 0.03, 95% CI = [-0.2288, -0.1054]) were found to fully mediate the longitudinal relationship between SA at T1 and PW at T3. The longitudinal serial mediation model accounted for 32% of the variance in PW (R² = .32). Conclusions This study shows that SA leads to a decrease in adolescents' PF skills and their capacity to effectively manage their emotional reactions over time, which in turn leads to lower PW levels. The findings emphasize the potential of interventions to improve PF and ER skills in alleviating SA-related mental health problems in adolescents. The findings also suggest that both strengthening PF and ER skills separately and addressing them simultaneously could significantly increase the effectiveness of treatment approaches.