The goal of this clinical trial is to learn if the Ultra-Brief Interpersonal Psychotherapy for Adolescents with Suicidal Ideation (IPT-A-SCI) works to reduce suicidal thoughts and behaviors in children and adolescents. The study will also examine whether treatment effects continue after treatment ends and whether some participants benefit more from the intervention than others. The main questions it aims to answer are:

Does IPT-A-SCI reduce suicidal thoughts and behaviors in children and adolescents? Do the effects of IPT-A-SCI continue three months after treatment ends? Do some children and adolescents benefit more from IPT-A-SCI than others?

Participants will:

Receive IPT-A-SCI treatment consisting of five weekly sessions Complete questionnaires before treatment, during treatment, at the end of treatment, and three months after treatment ends Have their parents complete questionnaires at the same time points

IPT-A-SCI (Ultra-Brief Crisis Interpersonal Psychotherapy for Adolescents with Suicidal Ideation) is a manualized five-session crisis intervention based on Interpersonal Psychotherapy (IPT) principles.

IPT-A-SCI is designed for children and adolescents aged 8-18 presenting with suicidal ideation or behavior. The intervention combines IPT principles with the Safety Planning Intervention and includes a three-month post-intervention contact protocol.

This is a single-group, pre-post interventional study with repeated measures collected at four time points. All participants will receive the IPT-A-SCI intervention. There is no control or comparison group in this study, as the research focuses on within-person mechanisms of change and moderators of treatment response rather than between-group comparisons.

Participants will be recruited from the Child and Adolescent Clinic at Geha Mental Health Center through emergency room referrals, outpatient providers, and treating therapists at the clinic. Initial evaluation and suicide risk assessment will be conducted by experienced clinical staff according to established clinical guidelines for suicide risk assessment in adolescents.

Up to 120 participants will be enrolled over an estimated two-year recruitment period.

During the three months following treatment, participants will receive three personalized emails at 2 weeks, 1 month, and 2 months post-treatment. A follow-up session will take place three months after treatment completion. Psychiatric or psychosocial treatment may continue as usual during IPT-A-SCI.

Statistical Analysis Plan:

Three complementary analytic frameworks will be used:

1. Modeling within-person change across therapy
2. Examining associations between changes in proposed mechanisms of change and changes in suicidality
3. Identifying participant characteristics associated with differential treatment response Individual Growth Curve Modeling (IGCM) will be used to examine trajectories of change across the four assessment time points for proposed mechanisms of change, including hope, perceived social support, emotional processing, family conflict, and interpersonal functioning.

Latent Change Score (LCS) modeling will be used to assess changes in suicidal ideation and related clinical outcomes from baseline to post-treatment and follow-up. Associations between changes in proposed mechanisms and changes in suicidality will be examined to identify factors that may contribute to treatment effectiveness.

Linear Mixed-Effects Models (LMMs) will be used to examine whether treatment effectiveness varies according to baseline participant characteristics, including initial suicide risk severity and other demographic and clinical variables. These analyses will identify moderators of treatment response and determine which participants derive the greatest benefit from the intervention.

Missing data will be handled in accordance with established best practices for longitudinal clinical research. The analytic approaches described above accommodate missing data under missing-at-random assumptions.

Data Collection and Management:

• Questionnaires will be completed by participants and parents at all assessment time points.
• The Columbia-Suicide Severity Rating Scale (C-SSRS) will be administered by clinicians during treatment sessions.
• A unique trial identification number will be assigned at recruitment and used across all study materials.
• All study data will be retained in accordance with Good Clinical Practice (GCP) guidelines.

Safety Monitoring and Ethical Considerations:

This study focuses on children and adolescents at risk for suicide. The Child and Adolescent Clinic at Geha Mental Health Center is located on the grounds of a psychiatric hospital with a 24/7 emergency room. Participants presenting with acute suicidal crisis during the study may be referred immediately for emergency psychiatric evaluation.

All treating clinicians are trained in suicide risk assessment and management. Adverse events, including worsening suicidal ideation or behavior, will be documented and reported in accordance with Helsinki Committee requirements and Good Clinical Practice guidelines.

No formal Data Safety Monitoring Board (DSMB) is in place for this study given its single-site naturalistic design. Clinical oversight will be provided through routine supervision and case conferencing.

Inclusion Criteria:

• Children and adolescents aged 8-18 years presenting with suicidal ideation or behavior
• Suicide risk assessment indicating suitability for outpatient treatment,
• Fluency in Hebrew
• Ability to attend five weekly treatment sessions
• Written informed consent provided by parents or legal guardians
• Written informed assent/consent provided by participants in accordance with age and local ethical regulations

Exclusion Criteria:

• Acute medical or psychiatric condition requiring immediate inpatient treatment
• Linguistic, developmental, neurological, or intellectual limitations that prevent understanding of the treatment protocol or study procedures
• Inability to participate in outpatient psychotherapy