The goal of this clinical trial is to assess the effectiveness of a suicide prevention training program (Gatekeepers) tailored to university students in Spain. The main questions it aims to answer are:

• Does the training program improve suicide-related knowledge, attitudes, perceived behavioral control, and gatekeeper behaviors among students?
• Are there differences in training outcomes by gender, and how do they affect program engagement and effectiveness? Researchers will compare a Immediate Intervention Group (GTK-IG), which will receive the full training immediately, with a 2) the Delayed Intervention Group (GTK-DG), which will be a waitlist control during the first phase of the study, to evaluate the program's short- and medium-term impact, using both in-person and online formats. which will be a waitlist control during the first phase of the study.

Participants will:

• Be randomly assigned to the intervention or control group, choosing between in-person or online training
• Complete online surveys at three timepoints: before the program (T0), immediately after (T1), 2-3 months later (T2), and 9-12 months follow-up (T3).
• Attend two 3-hour training sessions covering key suicide prevention competencies
• Participate in a follow-up session with focus group discussion to qualitatively assess retention and use of learned skills
• Complete validated questionnaires on suicide prevention literacy, attitudes, stigma, and self-reported gatekeeper behaviors This trial includes validation of the Spanish versions of the WISE (Willingness to Intervene Against Suicide Enhanced Questionnaire) and ACT as Gatekeeper measures. The study is registered at ClinicalTrials.gov and follows CONSORT and SPIRIT guidelines. Ethical approval was granted by the Human Research Ethics Committee at the University of Valencia.

Title: Effectiveness of a Multicenter Suicide Prevention Gatekeeper Program for Students at Spanish Universities (GTK-UNI)

Background and Rationale:

Suicide is a leading cause of death among young adults worldwide, and university students represent a particularly vulnerable population due to psychosocial, academic, and transitional stressors. Despite the growing recognition of the importance of suicide prevention, few evidence-based interventions have been adapted for university environments in Spain. Gatekeeper Training (GKT) programs are short interventions designed to equip non-specialists with the ability to recognize warning signs, intervene appropriately, and refer at-risk individuals to professional support. This project, titled GTK-UNI, aims to develop, implement, and rigorously evaluate the effectiveness of a Gatekeeper Training program adapted to Spanish university settings.

Study Objectives:

The main objective of this multicenter randomized controlled trial (RCT) is to evaluate the effectiveness of a suicide prevention Gatekeeper program delivered to university students. The program will be tested both in online and face-to-face formats to determine its utility, scalability, and long-term impact. Specific aims include:

Designing a structured and culturally relevant GKT program for university students in Spain.

Validating two measurement tools in Spanish: the Willingness to Intervene Against Suicide Enhanced Questionnaire (WISE) and the ACT as Gatekeeper questionnaire.

Implementing the program in both in-person and online formats to ensure accessibility.

Measuring the impact of the training on knowledge, attitudes, perceived control, and actual gatekeeper behaviors, with gender-stratified analyses.

Evaluating participants' adherence to and satisfaction with the program, identifying gender-related barriers and facilitators to participation.

Collecting qualitative data through focus groups to explore how gender norms influence program engagement and effectiveness.

Disseminating results to support gender-sensitive suicide prevention strategies in educational and mental health policy.

Contributing to translational research by developing a validated guide for university-level suicide prevention planning.

Methods:

This is a multicenter, two-arm, randomized controlled trial with a waitlist control group. Participants are university students (age ≥18) from multiple Spanish universities, recruited via university mailing lists, social media, student associations, and institutional partnerships. Recruitment materials clarify that the training is a suicide prevention initiative and outline the voluntary nature of participation.

Randomization and Conditions:

After providing informed consent, participants are randomly assigned to one of two groups:

Intervention group (GTK-IG): Receives the Gatekeeper Training immediately, either in online or face-to-face format, depending on their preference.

Delayed Intervention Group (GTK-DG): which will be a waitlist control during the first phase of the study and will receive the interventions after T2 (2-3 months later).

Training Format and Content:

The GTK-UNI program consists of 6 modules delivered in two 3-hour sessions over two weeks. Modules include:

Introduction to suicidal behavior and epidemiology

Recognition of warning signs and risk/protective factors

Crisis intervention and suicide first aid strategies

Safety planning and community resources

Ethics and self-care for gatekeepers

Practical evaluation and case simulation

Evaluation Timeline:

T0 (Baseline): Online survey before intervention

T1 (Post-intervention): Immediately after last session (two weeks after T0)

T2 (Follow-up): To be conducted 2 months after T1, with a booster session and focus group for GTK-GE participants scheduled approximately 2.5 months after T0.

T3 (Follow up 2): 9-12-month after T1.

After each session: Assessments will be also administered to monitor progressive skill acquisition.

Control group receives the training after T2 (approximately 2.5-3 months after T0)

Instruments:

Primary outcome measures include:

WISE Questionnaire (Aldrich & Cerel, 2024): Measures attitudes, norms, perceived control, and intention to intervene.

ACT as Gatekeeper (Nozawa et al., 2020): Evaluates actual gatekeeper behaviors.

Secondary outcomes:

LOSS-SF (Calear et al., 2022): Assesses suicide literacy. SOSS-SF (Batterham et al., 2012): Measures stigma toward suicide. PHQ-9 (Kroenke et al., 2001): Assesses depressive symptoms. Additional variables include emotional burden, satisfaction, gender, and open-ended responses on program perception.

Rosenbertg self steem (Rosenberg, 1965) Program satisfaction and perceived utility. Ad hoc questions. Suicidal behavior (self and others). Ad hoc questions. Intersession skill monitoring: ad hoc questions.

Ethical Considerations:

The study protocol was approved by the Human Research Ethics Committee of the University of Valencia (ID: UV-INV_ETICA-3746002). The project adheres to the Declaration of Helsinki, the Madrid Declaration of the World Psychiatric Association, and national ethical standards. All participants will provide informed consent and retain the right to withdraw at any time. Data will be anonymized and securely stored, with no sharing of personal information with third parties.

If participants report emotional distress or indicate prior suicidal behavior as a motivation for joining, LIme Survey platform triggers an emergency screen with contact information for psychological services and crisis helplines. Professional referral may be offered as needed.

Sample Size and Power Calculation:

Sample size calculations were based on previous studies evaluating GTK, assuming medium effect sizes for attitudinal and self-efficacy outcomes (Cohen's d = 0.50), a power of 0.80, and α = 0.05. Allowing for an estimated attrition rate of 20-25%, the target sample size was set to ensure sufficient statistical power for mixed-model and between-group analyses. The final recruitment goal was approximately 420 participants, distributed evenly between experimental conditions.

Data Collection and Analysis:

All assessments are administered through the secure Lime Survey-UV digital platform. Quantitative data will be analyzed using SPSS v29, following CONSORT guidelines. ANOVAs, χ² tests, and mixed-effects models will be used to analyze group-by-time interactions. Model fit indices for psychometric validation will be assessed using JASP. Qualitative data from focus groups will be analyzed thematically using NVivo or ATLAS.ti.

Collaborating Institutions:

University of Basque Country UPV/EUH

The principal investigators (Dr. Sandra Pérez and Dr. Monika Salgueiro) coordinate inter-university collaboration and oversight.

Inclusion Criteria:

• Be 18 years of age or older.
• Be currently enrolled as a university student in a Spanish university.
• Have access to the internet via personal computer, smartphone, or tablet (only applicable for participation in the online format).
• Acknowledge that the program offered is a suicide prevention training intervention.
• Provide informed consent to participate.

Exclusion Criteria:

• Inability to understand Spanish (the program will be delivered exclusively in Spanish).
• Inability or unwillingness to commit to attending both training sessions (regardless of whether the participant ultimately continues in the study).

Individual participant data will be available after deidentification

The data will be available immediately following publication

The data will be available to anyone who wishes to access them.