The novel group treatment program Training for Awareness, Resilience, and Action (TARA) was developed to target specific mechanisms based on neuroscience findings in adolescent depression and framed within the National Institute of Mental Health Research Domain Criteria. TARA contains training of autonomic and emotional self-regulation, interoceptive awareness, relational skills, and value-based committed action.We performed a single-arm trial to test the feasibility and preliminary efficacy of TARA in reducing depression and anxiety levels and assessed whether the specific targeted domains of function reflected the hypothesized symptom change. Twenty-six adolescents (14-18 years old, 7 males and 19 females) participated in the 12-week group program. Assessment was performed before (T0), immediately after (T1), and 3 months after the end of TARA (T2).Significant improvement was seen in depression symptoms (Reynolds Adolescent Depression Scale Second Edition) between T0-T1 (t-value = -3.56, p = 0.002, CI = -6.64, -1.77) and T0-T2 (t-value = -4.17, p < 0.001, CI = -11.20, -3.75) and anxiety symptoms (Multidimensional Anxiety Scale for Children) between T0-T1 (t-value = -2.26, p = 0.033, CI = -4.61, -0.21) and T0-T2 (t-value = -3.06, p = 0.006, 95% confidence interval = -9.02, -1.73). Significant improvements in psychological flexibility, sleep, and mindfulness skills were also found between T0 and T2.The sample size was small without a control condition. The pilot design did not allow for testing the hypothesized brain changes and effect of TARA on relevant systemic biomarkers.TARA is feasible in a sample of clinically depressed and/or anxious adolescents and preliminary efficacy was demonstrated by reduced depression and anxiety symptoms. The specific symptom and behavioral outcomes corresponded well with the hypothesized mechanisms of change.