Abstract
Objective: To evaluate the effectiveness of a school-based Positive Mental Model within the MTSS framework in improving reproductive health knowledge and mental well-being among adolescent girls.
Methodology: This quasi-experimental pretest–post-test control group design was applied in two public senior high schools in South Jakarta and West Jakarta. The study was conducted from March to July 2024. The intervention group was recruited from a public school in South Jakarta, while the control group was selected from a comparable public school in West Jakarta. The 12-week intervention followed the Multi-Tiered System of Supports (MTSS) framework, consisting of weekly sessions. A total of 70 participants were included in the analysis (intervention n=35, control n=35). Instruments included the Depression Anxiety Stress Scale–Youth (DASS-Youth), the Adverse Childhood Experiences–International Questionnaire (ACE-IQ), and a reproductive health knowledge questionnaire. Assessments were conducted at baseline (week 0), mid-intervention (week 4), and endline (week 12). The data were analysed using descriptive statistics, Spearman’s rho correlation, Wilcoxon signed-rank, Mann–Whitney U, and Friedman tests.
Results: High ACE exposure was reported by 69.2% of participants. Moderate–severe depression, anxiety, and stress were present in 35 %, 31.6%, and 20.0%, respectively. Knowledge was moderate in 51.7% and good in 46.7%. Tier distribution was 30% Tier 1, 49.2% Tier 2, and 20.8% Tier 3. The intervention group exhibited significant reductions in their DASS-Youth scores, while the control group did not exhibit significant improvements in knowledge across all levels (p<0.05).
Conclusion: The Positive Mental Model within the MTSS framework effectively improved reproductive health knowledge and reduced psychological distress among adolescent girls. Integrating this approach into existing school-based health and counselling programs could enhance sustainability and support early identification of students who need assistance.

Key words: Adolescent girls, Multi-Tiered System of Supports, reproductive health, adverse childhood experiences.