Effectiveness of a Group Behavioral Activation Intervention for Subthreshold Depression in Chinese University...

Subthreshold depression (SD) is prevalent among Chinese undergraduates, often leading to impaired academic and social functioning, and elevated risk for major depressive disorder (MDD). Behavioral activation (BA) is an evidence-based treatment for depression, but its effectiveness and mechanisms for SD in this population remain relatively limited. This randomized controlled trial (RCT) aimed to evaluate the efficacy of a culturally adapted, group-based BA intervention for reducing SD symptoms, increasing environmental rewards (ERs), and promoting behavioral activation. Forty-one undergraduates with SD were randomly assigned to six 90-minute sessions of face-to-face BA group (n = 21) or a waitlist control (n = 20). Compared to the waitlist, the BA group showed significantly greater reductions in depressive symptoms (Beck Depression Inventory-II) from baseline to post intervention and this improvement was sustained in follow-up (Group × Time interaction, F(2,78) = 6.79, p < 0.05, partial η² = 0.15), alongside significant increases in both BA (Behavioral Activation for Depression Scale) and ERs (Environmental Reward Observation Scale) level; whereas in the control group, no significant difference was observed in the level of BA, ERs and depressive symptoms between baseline and post intervention. However, ERs did not significantly mediate the effect on depressive symptoms (indirect effect = -0.3, 95% CI [-0.85, 0.13]). Findings support BA as a scalable, culturally relevant campus intervention and motivate larger trials to optimize mediator timing and test a more comprehensive model of change, incorporating mechanisms of both punishment attenuation (e.g., reduced avoidance) and motivational recalibration (e.g., social connectedness).