HENKA: Growing in Emotional Well-being.

The quantitative phase uses school-level cluster sampling: recruitment was coordinated with the Department of Education and the Department of Health of the Government of Catalonia, and schools voluntarily enrolled in either the HENKA intervention group (target at least 100 schools) or the control group (target at least 25 schools), depending on whether they formalized full participation in the program or chose to take part in the evaluation component only. The first-year secondary school cohort served as the sampling cluster, with additional cohorts progressively enrolled across successive academic years, starting in 2023-2024, until the target sample size was reached; each cohort was followed longitudinally until the third year of secondary school. The intervention comprises student training, consisting of eight approximately 55-minute classroom sessions covering self-efficacy/self-esteem, emotional self-regulation, assertiveness, interpersonal skills, and mindfulness. This training is delivered by teachers during school hours, and the teachers have previously received training from specialist staff (train-the-trainer program). In some sessions, teachers are accompanied by Community Emotional Well-being Representatives (RBEC), health professionals provided by the Department of Health who support classroom delivery and help identify and manage mental-health-related situations among students. Families attend parent workshops. Control schools continue with their usual mental health talks and resources and are offered the HENKA materials after the study ends. Results are assessed through validated online questionnaires (REDCap) at up to six time points over three academic years. A sample size calculation performed a priori with G*Power 3.1.9.7 (effect size 0.2, alpha 0.05, power 0.95) indicated a minimum of 1,084 participants (542 per control and intervention group). In addition, a qualitative phase is conducted through focus groups with each participant segment (adolescents, families, educational professionals, and key regional well-being stakeholders from the BxB, RBEC and PSiE programs), held during the second and third trimesters of the 2024-2025 and 2025-2026 academic years, to explore participants' experiences and perspectives on the HENKA program.

Inclusion criteria

• Enrolled in a lower secondary school (ESO) in Catalonia, Spain.
• Adolescents enrolled in 1st, 2nd or 3rd year of ESO.
• Adolescents under 18 provide assent to participate; parents/guardians provide written informed consent.
• Parents/guardians and teachers who sign informed consent participate in the program evaluation.

Exclusion criteria

• Parents/guardians who do not sign informed consent for minors under 18.
• Adolescents who do not assent to participate.
• Parents/guardians who do not sign their own informed consent.
• Teachers who do not sign their informed consent.