Low-threshold secondary and tertiary suicide prevention measures for individuals with suicid-related thoughts and behaviors: a scoping review

Abstract

Introduction Suicide rates remain persistently high in many regions worldwide, including Germany. The 2024 German National Suicide Prevention Strategy emphasizes the strengthening of evidence-based approaches. In this context, a comprehensive synthesis of low-threshold secondary and tertiary suicide prevention measures for adults is required. Methods This scoping review set out to address this need and followed established methodological guidance and the PRISMA-ScR reporting guidelines. PubMed and Web of Science were searched on September 1, 2025, for studies published from January 1, 2005, onwards. To be eligible for inclusion, studies needed to examine low-threshold secondary or tertiary suicide prevention measures targeting adults with suicide-related thoughts and behaviors (STBs). Interventions focusing on primary medical care, psychotherapy, pharmacotherapy, gatekeepers and means restriction were excluded. Results Out of 1,897 records, 24 studies met the inclusion criteria. Most studies investigated voice-based (n = 9; 37.5%) and text-based (n = 7; 29.2%) crisis interventions within suicide prevention lifelines. These interventions consistently demonstrated reductions in suicidal ideation and psychological distress, with one exception: a moderated peer-to-peer forum. Outreach messages (n = 3; 12.5%) and web-based educational (and counseling) measures (n = 5; 20.8%) showed promising but more heterogeneous findings. Outcomes indicated potential benefits, though the evidence was less consistent. Discussion The findings suggest that voice- and text-based crisis interventions are supported by a growing evidence base, primarily demonstrating short-term effects. Web-based educational (and counseling) measures and outreach messages, while heterogeneous, show potential for individuals with STBs through the use of emerging technologies. Future research should examine mechanisms of action, long-term outcomes, and employ randomized controlled trial designs (where feasible) to strengthen the evidence base. Systematic review registration https://doi.org/10.17605/OSF.IO/K2B83.