This is a randomized controlled trial that aims to compare the effectiveness of two psychological treatment approaches: the Attempted Suicide Short Intervention Program (ASSIP) and Acceptance and Commitment Therapy (ACT). The study seeks to determine which of these two methods is more effective in reducing suicidal ideation and mental pain in individuals who have recently attempted suicide.

In this study, 60 participants with a history of suicide attempts will be randomly assigned to three groups. One group will receive ASSIP in addition to treatment as usual (TAU), the second group will receive ACT alongside TAU, and the third group will be a control group receiving TAU only. The results will be assessed using the Beck Scale for Suicide Ideation (BSSI) and the Orbach & Mikulincer Mental Pain Scale (OMMP) at three stages: pre-test, post-test, and follow-up.

The ultimate goal of this research is to provide valuable insights into the comparative effectiveness of ASSIP and ACT interventions for suicide attempters and to contribute to evidence-based suicide prevention strategies. The findings are expected to inform clinical practice and guide future research in this field.

Background and Rationale:

Suicide attempts are a major global public health concern and one of the leading causes of premature mortality, particularly among individuals aged 15 to 29 years. In Iran, as in many countries, suicide attempts represent a critical mental health issue requiring effective, evidence-based interventions. Two therapeutic approaches have demonstrated promising results in reducing suicidal ideation and preventing repeated attempts: the Attempted Suicide Short Intervention Program (ASSIP) and Acceptance and Commitment Therapy (ACT).

ASSIP is a brief, structured, narrative-based intervention developed to address the underlying personal crisis and cognitive-behavioral mechanisms that lead to suicidal behavior. It typically involves three to four sessions, followed by long-term follow-up contacts. ACT is a third-wave behavioral therapy aimed at increasing psychological flexibility and reducing experiential avoidance, often associated with suicidal crises.

Despite evidence supporting both methods internationally, little research has compared their effectiveness in the Iranian context.

Study Overview:

This randomized controlled trial will enroll 60 adults with a recent history of suicide attempt, identified through the Eslamshahr Health Network. Participants will be randomly assigned to one of three groups:

1. ASSIP plus treatment as usual (TAU)
2. ACT plus TAU
3. TAU only (control) Interventions will be delivered in an outpatient health center setting. The ASSIP group will receive three core sessions (with a possible fourth session) delivered according to the official ASSIP manual. The ACT group will receive four to five individual sessions following the "ACT for Life" protocol, specifically adapted for suicide prevention.

Assessment and Follow-up:

The primary outcomes are suicidal ideation and mental pain, assessed using validated Persian versions of the Beck Scale for Suicide Ideation (BSSI) and the Orbach & Mikulincer Mental Pain Scale (OMMP). Assessments will occur at baseline (pre-test), immediately after treatment (post-test), and one month after intervention (follow-up). Data will be analyzed using SPSS v27, applying descriptive statistics, analysis of covariance, and post hoc comparisons.

Significance:

This study is expected to generate context-specific evidence on the comparative effectiveness of ASSIP and ACT in reducing suicidal ideation and mental (or psychological) pain in Iranian suicide attempters. The findings will help inform mental health services in Iran and contribute to global suicide prevention strategies by clarifying which short-term, evidence-based intervention is more effective and feasible in similar healthcare settings.

Inclusion Criteria:

• Being 18 years of age or older
• Having the ability to read and write
• Providing informed consent to participate in the study
• Having at least one suicide attempt in the past 4 months

Exclusion Criteria:

• Having a severe psychiatric or physical illness that interferes with the treatment process
• Receiving concurrent structured psychological interventions (other than TAU) that may interfere with the study's treatment process.
• Lack of informed consent to participate in the study
• Substance abuse based on DSM-5 criteria

The individual participant data (IPD) will not be shared due to the highly sensitive and confidential nature of the data collected from suicide attempters. The protocol for this study will be published in a scientific journal upon peer review approval. Furthermore, after data collection and analysis are complete, the results will be published in a scientific journal following peer review approval.

Only participants will be unaware of their group assignment.