Stratified-Care School-Based Intervention for Adolescent Suicidal Ideation

Acceptability and Feasibility of a Stratified-Care School-Based Intervention for Adolescent Suicidal Ideation in Chile: A Study Protocol

Background. Suicidal ideation and depressive symptoms are highly prevalent among adolescents, with suicide representing a leading cause of death in this age group worldwide. School-based indicated prevention programs using cognitive behavioral therapy (CBT) have shown promise in addressing these mental health challenges. The Reframe-IT+ (Chile) and CARIBOU (Canada) programs are CBT-based, individually delivered interventions targeting adolescents at risk of suicide. This study aims to evaluate a culturally adapted stratified-care model using these two interventions, matched to depressive symptom severity.

Methods. This is a quasi-experimental, single-arm study with pre-post assessments and follow-ups at 3, 6, 9, and 12 months. Six secondary schools with high socioeconomic vulnerability in Santiago, Chile, will participate. Students with suicidal ideation and mild/moderate depressive symptoms (PHQ-9 < 20) will be offered Reframe-IT+, while those with severe symptoms (PHQ-9 ≥ 20) will be offered CARIBOU. Primary outcomes include the acceptability of CARIBOU, feasibility of the stratified-care model, and implementation fidelity. Secondary outcomes include reductions in suicidal ideation, depression, anxiety, hopelessness, and improvements in functioning, quality of life, behavioral activation, emotional regulation, and problem-solving skills.

Discussion. This protocol addresses the need for scalable, culturally sensitive interventions for adolescent suicide prevention in school settings. By evaluating both the process and early outcomes of a stratified-care approach, this study will generate valuable evidence to inform future large-scale effectiveness trials and policy development in adolescent mental health.

Suicide among adolescents and young people is a highly prevalent global issue, with suicidal ideation reaching rates of approximately 18% and suicide attempts around 6% (1). According to the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD), suicide ranks as the fifth leading cause of death among individuals aged 10 to 24 (2), with a mortality rate of 6.0 per 100,000 in this age group (3). Suicide mortality increases with age: 1.2 per 100,000 among those aged 10-14; 6.7 among those aged 15-19; and 10.6 among those aged 20-24 (3). In Latin America, suicide mortality rates surpass global averages, reaching 9.8 per 100,000, and in Chile, the rate is 7.2 per 100,000 (3).

Numerous risk factors are associated with suicide, including genetic, biological, psychological, and social factors (4,5). Each case of suicide is caused by a unique, dynamic, and complex interaction of these elements (4,5). However, depression remains the most frequently reported common factor (4). A recent literature review found that between 50-65% of suicide cases met criteria for depression (4). Regarding its broader impact, depressive symptoms are even more prevalent than suicidal ideation, with global rates of 43.9%, including mild, moderate, and severe cases (6). Moreover, the number of depression cases among adolescents has grown exponentially, with a 21.6% increase in total cases and a 19% increase in incidence compared to the 1990s (7). In Chile, adolescent depression is estimated to affect 8.3% of the population, yet fewer than half receive mental health care (8).

Secondary schools are recognized as appropriate, accessible, and effective settings for suicide (9) and depression prevention programs (10) for adolescents. School-based interventions offer broad reach and enable large-scale prevention efforts (9,10). Evidence shows that such programs improve suicide awareness and coping skills to reduce suicidal thoughts and attempts (9,11,12). However, indicated interventions-those targeting at-risk individuals with clinical or psychosocial approaches such as cognitive-behavioral therapy (CBT)-remain less common in school settings (13), despite their established efficacy in other contexts (13), underscoring the need for further research on their implementation in schools.

Two CBT-based programs have demonstrated effectiveness and safety in reducing suicidal ideation and depressive symptoms. Both are indicated interventions, meaning they target individuals already at risk and are delivered individually.

The Reframe-IT program, developed in Australia, targets behavioral activation, cognitive restructuring, emotion regulation, stress tolerance, and problem-solving skills (14). It includes eight digital sessions designed for delivery by school well-being staff (14). A pilot randomized controlled trial in Australia showed greater reductions in suicidal ideation, depression, and hopelessness among the intervention group than controls, although differences were not statistically significant due to insufficient statistical power (14). In Chile, the research team collaborated with the University of Talca for over four years to culturally adapt Reframe-IT, developing Reframe-IT+ by adding five face-to-face sessions to the original eight. An initial pilot study with 52 participants showed high acceptability and reductions of 15.2 points in suicidal ideation and 3.5 in depressive symptoms (15). A subsequent RCT with 1,546 screened students and 100 randomized participants demonstrated significant decreases of 6.7 points in suicidal ideation and 3.1 in depressive symptoms (16). Following these positive results, a scaled-up quasi-experimental study in Santiago (CEC2024061) included 75 students and showed preliminary reductions of 2.5 points in suicidal ideation and 3.2 in depressive symptoms.

The CARIBOU program, developed in Canada, targets behavioral activation, cognitive restructuring, problem-solving, and communication skills (17). It consists of 16 sessions facilitated by trained professionals from diverse backgrounds. A non-randomized pilot study showed a 2-point reduction in depressive symptoms (17). Moreover, 80% of participants reported program engagement, and facilitators achieved 95% fidelity in implementation (17). The research team has initiated contact with Dr. Darren Courtney, CARIBOU's lead developer, to begin its cultural adaptation in Chile as part of the present study.

This study proposes a stratified-care intervention model in which treatment intensity is matched to individual needs, ensuring appropriate levels of care. Adolescents with suicidal ideation will be offered Reframe-IT+ if they present with mild or moderate depressive symptoms, and CARIBOU if they present with severe symptoms.

METHODOLOGY General Objective The general objective of this study is to examine the acceptability of the CARIBOU program and the feasibility and fidelity of implementing a stratified-care approach tailored to the needs of adolescents with suicidal ideation. Under this model, students with mild or moderate depressive symptoms (PHQ-9 < 20) will be offered the Reframe-IT+ program, and those with severe depressive symptoms (PHQ-9 ≥ 20) will be offered the CARIBOU program. Additionally, this study aims to explore the efficacy of a stratified-care intervention in adolescents at risk for suicide and with depressive symptomatology.

Inclusion Criteria:

• Inclusion Criteria for Educational Institutions

  • Located in Santiago, Chile.
  • Secondary education level (grades I-IV Medio).
  • Coeducational schools.
  • At least two classes per grade level in secondary education.
  • A minimum of 30 students per class.
  • Socioeconomic vulnerability level of ≥ 50%, as measured by the School Vulnerability Index (Índice de Vulnerabilidad Escolar - IVE-SINAE), which includes factors such as parental education and total household income.

Inclusion Criteria for Students

• Enrolled in grades I, II, or III Medio.
• Suicidal ideation within the past month, defined as a score ≥ 3 on the Columbia-Suicide Severity Rating Scale (C-SSRS).
• For the Reframe-IT+ program: mild or moderate depressive symptoms, defined as a PHQ-9 score < 20.
• For the CARIBOU program: severe depressive symptoms, defined as a PHQ-9 score ≥ 20.

Exclusion Criteria:

• Exclusion Criteria for Students

  • Participation in a structured suicide prevention program (Reframe-IT+) during 2024.
  • Severe psychotic symptoms, such as perceptual disturbances or delusional ideas, assessed during the eligibility interview.
  • Suicide attempt(s) in the past three months, assessed during the eligibility interview.