<![CDATA[ABSTRACT Middle adolescence is highly vulnerable to academic stressors that precipitate anxiety, overthinking, and sleep disturbance. A school-based screening at a public junior high school in Bandung revealed that 58.8% of ninth-grade students experienced mild-to-severe anxiety, characterized by persistent worry (48.8%), cognitive rumination (34.1%), and insomnia (37.4%). This study evaluated a youth-centered anxiety management intervention, emphasizing how physical spatial configuration may influence cognitive absorption and knowledge retention. A quasi-experimental, one-group pre-test/post-test design was conducted with 212 ninth-grade students. The 60–65-minute intervention integrated education on uncertainty-induced anxiety with immediate psychomotor training in grounding and deep breathing exercises. Data were analyzed using the Wilcoxon Signed-Rank Test, stratified by intervention setting. Overall knowledge scores improved significantly from 85.66 to 91.13. However, stratification by intervention setting revealed divergent outcomes: micro-classroom cohorts (Classroom 9C: p = 0.018; Classroom 9D: p 0.001) demonstrated statistically significant improvements, whereas the large auditorium cohort (n = 101, all female) showed statistical stagnation (p = 0.410). This stagnation was strongly influenced by a ceiling effect, reflected in 77.2% unchanged scores among female students with high baseline knowledge (mean = 90.69), compounded by acoustic constraints and class congestion. Conversely, micro-classroom settings may have supported psychological safety and engagement among male cohorts. Physical spatial configuration may influence the effectiveness of school-based mental health education. Future school-based mental health protocols should prioritize micro-classroom clustering where feasible and transition advanced cohorts from written cognitive assessments toward longitudinal psychomotor and clinical outcome metrics. Keywords: Adolescent Mental Health, School Health Nursing, Spatial Configuration, Anxiety Management, Youth-Centered Approach, Grounding Exercises.]]>
