Abstract
Our research investigated how a smartphone application utilizing behavioral activation principles affects depression levels in young adult populations. A total of 67 participants aged 20-30 years with clinically significant depressive symptoms (CESD-11 ≥ 16) were divided into treatment (n = 31) and comparison conditions (n = 36) through randomization procedures. Participants in the experimental group engaged with a BA-based mobile application (Maummove) over an eight-week period, while those in the control group completed weekly assessments without intervention. Depression, perceived stress, and life satisfaction were measured at baseline and postintervention using the CESD-11, PSS, and SWLS, respectively. The results indicated that the experimental group exhibited significant reductions in depression (Cohen's d = 1.03) and stress (Cohen's d = 0.99) compared to the control group, which showed minimal changes. Improvements in life satisfaction were observed in the experimental group, with a smaller effect size (Cohen's d = 0.23). Time-series analyses demonstrated that depressive symptoms decreased progressively throughout the intervention period, falling below the clinical cutoff by the seventh week. These findings provide preliminary evidence that BA-based mobile applications may offer a promising, accessible approach to reducing depressive symptoms and perceived stress in young adults, though replication in larger samples with longer follow-up periods is needed to establish generalizability. This study highlights the potential of digitally delivered BA interventions as a viable alternative or complement traditional mental health services, particularly for populations facing barriers to face-to-face care.