The goal of this observational study is to learn more about people who come to emergency departments in Spain after a suicide attempt and to find ways to prevent another attempt. The main questions are whether some personal, social, biological, and clinical factors are linked to a higher risk of trying again, and whether different follow-up strategies can help lower this risk over time.

Researchers will follow a total of about 3,600 people who attempted suicide: around 1,800 who were already recruited in a previous study and about 1,800 new participants who will be added in this project, in several hospitals across Spain.

Some participants may also be invited to give blood samples, answer online questionnaires, or use smartphone-based tools to understand better changes in mood and suicidal thoughts in daily life. A subset of participants may be invited to join separate clinical trials that test different follow-up programs to prevent another suicide attempt; these trials will be registered and described in their own study records.

BACKGROUND: Suicide is the leading preventable cause of death in the world. In Spain, the data show a growing trend in recent years, indicating the need to implement evidence-based prevention strategies. OBJECTIVES: The main objective of this study is to continue monitoring a previously established cohort of 1,800 suicide attempts and extend it to include 3,600 cases. The secondary objectives are: 1) to identify risk factors (1a: socioeconomic, psychological, and clinical, 1b: biological, and 1c: genetic) that can predict a repeat attempt, 2) to study suicidal behavior in the pandemic and post-pandemic times, 3) to identify phenotypes related to suicidal ideation and behavior using momentary ecological assessment and 4) to determine the efficacy of secondary prevention programs for suicidal behavior compared with treatment as usual (TaU). METHOD: Multi-center-coordinated cohort study with five nested clinical controlled trials. The participants will be recruited in nine centers distributed in the Spanish territory. The primary variable will be the time to repeat the attempt.

SUB-PROJECT 1: a) long-term follow-up study (5 years) of a cohort of suicide attempts (total n = 3600 cases), b) study of biological and c) genetic markers associated with a suicide attempt. SUB-PROJECT 2: will study suicidal ideation and behavior phenotypes using momentary ecological assessment and experience sampling. SUB-PROJECT 3: will evaluate the efficacy of different secondary prevention programs compared to TaU.

Inclusion Criteria:

• Individuals (above 12 years old) who present to participating Spanish hospital emergency departments after a suicide attempt, as defined by self-injurious behavior with at least some intent to die.
• Able to understand the study procedures and provide informed consent (or assent with parental/guardian consent for minors, according to local regulations)
• Sufficient proficiency in Spanish to complete study assessments

Exclusion Criteria:

• Suicide attempts clearly judged as accidental or without suicidal intent
• Severe cognitive impairment, intellectual disability, or neurological condition that, in the opinion of the clinical team, prevents valid assessment or informed consent
• Acute medical instability that makes participation in research procedures unsafe.
• Any condition or circumstance that, in the opinion of investigators, would seriously interfere with participation or follow-up in the cohort.

Individuals (adolescents and adults) who present to the emergency departments of participating hospitals in Spain after a suicide attempt. The study will follow approximately 3,600 participants (about 1,800 already enrolled in a previous cohort and about 1,800 newly recruited) for up to 3 years to examine suicidal behavior and related risk and protective factors

Individual participant data (IPD) will not be shared because the dataset includes highly sensitive information on suicidal behavior collected in a limited number of centers, which increases the risk of re-identification even after de-identification. Data sharing is therefore restricted to protect participant privacy and comply with ethical and regulatory requirements.