The goal of this clinical trial is to learn if a structured expressive writing program can help reduce suicidal thoughts in adolescents and young adults who have experienced suicidal thoughts, suicide attempts, or self-harm. The study will include participants aged 13 to 24 years who are receiving mental health care or have recently been identified as being at risk for suicide.

The main questions the study aims to answer are:

• Does a structured expressive writing program lower suicidal thoughts compared with usual care alone?
• Does the program improve depression, impulsivity, and self-esteem?

Researchers will compare participants who receive the expressive writing program together with treatment as usual to participants who receive treatment as usual alone.

Participants will:

• Be randomly assigned to one of two groups: a writing program group or a usual care group
• Complete questionnaires about mood, suicidal thoughts, and well-being at the start of the study, after 4 weeks, and after 8 weeks
• If assigned to the writing program group, complete guided writing activities several times per week for 4 weeks. Each writing session will take about 15 to 20 minutes and will focus on understanding emotions, personal experiences, relationships, and meaning in difficult experiences.

Researchers will study whether this writing program is a helpful and practical way to support young people who are experiencing suicidal thoughts or emotional distress.

Suicide represents a major public health concern among adolescents and young adults. In South Korea, suicide has consistently ranked as the leading cause of death among individuals aged 10-29 years. Preventive interventions targeting suicidal ideation and early stages of suicide risk are therefore urgently needed.

Existing evidence-based interventions for suicidal behaviors, including dialectical behavior therapy (DBT) and cognitive behavioral therapy (CBT), have demonstrated clinical effectiveness but require intensive therapist involvement and specialized training. These characteristics limit their scalability and accessibility in many community and school-based settings.

Expressive writing is a brief psychological intervention originally developed by Pennebaker and colleagues, in which individuals write about emotionally significant experiences. The intervention is believed to promote emotional labeling, cognitive processing, and narrative integration of stressful experiences. Neuropsychological research suggests that labeling emotions may reduce amygdala activation and facilitate regulation through prefrontal cortical mechanisms. Meta-analytic studies have also reported improvements in psychological outcomes among adolescents who engage in expressive writing.

However, randomized controlled trials evaluating expressive writing interventions specifically for adolescents and young adults at risk of suicide remain limited. In addition, most existing interventions are unstructured, which may limit their suitability for high-risk populations.

The present study aims to develop and evaluate a structured text-based expressive writing program designed for adolescents and young adults with suicide risk. The intervention is designed to promote emotional awareness, self-understanding, relational awareness, and meaning reconstruction through guided writing prompts delivered over four weeks.

Participants aged 13-24 years with a history of suicidal ideation, suicide attempts, or non-suicidal self-injury will be recruited from clinical and community settings. After screening and baseline assessment, participants will be randomly assigned to one of two groups:

1. Experimental group: 4-week structured expressive writing intervention plus treatment as usual (TAU)
2. Control group: TAU alone

Participants in the intervention group will complete guided writing exercises multiple times per week. Each writing session will take approximately 15-20 minutes and will be supported by structured prompts designed to facilitate emotional expression and cognitive processing.

Primary and secondary outcomes will be assessed at baseline, 4 weeks (post-intervention), and 8 weeks (follow-up). The primary outcome is change in suicidal ideation measured using the Beck Scale for Suicide Ideation (BSSI). Secondary outcomes include depressive symptoms, impulsivity, self-esteem, and help-seeking behavior.

The study is designed as a randomized controlled trial with parallel assignment. A total of 160 participants will be enrolled. The findings of this study may contribute to the development of accessible and scalable suicide prevention interventions for adolescents and young adults.

Inclusion Criteria:

• Adolescents or young adults aged 13 to 24 years.
• Individuals with a history of suicidal ideation, suicide attempts, or non-suicidal self-injury.
• Individuals currently receiving mental health services or who have been evaluated as having suicide risk within the past 6 months.
• Ability to read and write in Korean.
• For participants under 19 years of age, both participant assent and parental consent are required.

Exclusion Criteria:

• Individuals requiring immediate psychiatric hospitalization.
• Severe intellectual disability or neurodevelopmental disorder that prevents participation in writing activities.
• Acute psychosis or manic episode that would interfere with participation in the study.
• Participation in another suicide prevention clinical trial during the study period.

Individual participant data will not be shared due to the sensitive nature of the data and the need to protect participant confidentiality, particularly because the study involves adolescents and suicide-related mental health information.

Masking is not used in this study because the intervention involves a behavioral expressive writing program. Participants and researchers will be aware of the group assignments.