Background <p>Depression and anxiety disorders are highly prevalent and frequently co-occur, a comorbidity associated with greater chronicity and symptom severity. Access to evidence-based psychological interventions remains limited, particularly in resource-constrained settings. Digital interventions offer a scalable solution. This study evaluated the feasibility, acceptability, and preliminary efficacy of the Micro-Video Psychological Training Camp (MVPTC), a fully automated digital intervention based on integrative psychotherapy principles and targeting mild-to-moderate depression/anxiety and multidimensional mental health.</p> Methods <p>In this randomized controlled trial, 204 adults (aged 18–70) with mild-to-moderate symptoms were allocated to either the MVPTC intervention (8 self-guided sessions, <i>n</i> = 97) or waitlist control group (<i>n</i> = 107). The severity of depressive and anxiety symptoms served as primary outcomes, and psychological resilience as a secondary outcome. Exploratory outcomes included sleep quality, coping strategies, and perceived social support. All were measured at baseline, post-intervention, and at 1-month and 3-month follow-ups. Feasibility (dropout and adherence rates) and acceptability (satisfaction ratings) were also assessed.</p> Results <p>Participants (mean age 30.68 years, SD 7.6; 66.2% female, 33.8% male) exhibited a 36.08% dropout rate in the MVPTC group versus 8.41% in control group. The intervention led to significant, sustained reductions in depressive symptoms (Cohen’s <i>d</i> = 0.87 at T2, 0.99 at T3, 0.80 at T4; all <i>P</i> &lt; 0.01) and anxiety symptoms (Cohen’s <i>d</i> = 0.71 at T2, 0.75 at T3, 0.63 at T4; <i>P</i> ≤ 0.01). Significant improvements were also observed in psychological resilience (Cohen’s <i>d</i> =-0.97 at T3, -0.84 at T4; <i>P</i> &lt; 0.01) and sleep quality (ISI: Cohen’s <i>d</i> = 0.97–1.08; <i>P</i> ≤ 0.01). Coping strategies improved transiently (Cohen’s <i>d</i> =-0.58 at T2, -0.53 at T3; <i>P</i> &lt; 0.05), while perceived social support showed no sustained group differences despite temporary family/friend support increases at T3 (Cohen’s <i>d</i> =-0.55 to -0.68; <i>P</i> &lt; 0.05). Participants rated the intervention as acceptable, with an average satisfaction score of 3.06 out of 4 (SD = 0.41; <i>n</i> = 44).</p> Conclusions <p>The MVPTC is a promising, fully automated digital intervention that significantly and sustainably reduced core symptoms of depression and anxiety while enhancing psychological resilience and sleep quality over a 3-month period in adults with mild-to-moderate symptoms. Its effects on coping strategies and social support were less enduring. The program demonstrates potential for scalable implementation. Future research should focus on strategies to improve adherence and evaluate its effectiveness in broader, real-world settings.</p> Trial registration <p>Registered on Chinese Clinical Trial Registry (ChiCTR2100043725). Registered: February 27, 2021, <a href="http://www.chictr.org.cn/">http://www.chictr.org.cn/</a>.</p>