A systematic review of lethal means safety counseling interventions: impacts on safety behaviors and self-directed violence

For lethal means safety counseling (LMSC) interventions to reduce population-level suicide rates, interventions must be deployed across many settings and populations. We conducted a systematic search in 6 databases to review the current state of LMSC interventions across study designs, settings, intervention providers, populations, and injury prevention levels (eg, universal). Eligibility criteria were as follows: any individual or group receiving an LMSC intervention involving a human-to-human component aiming to influence adult behaviors related to lethal suicide methods, and outcome assessment of storage behaviors and/or suicidal self-directed violence (SDV). Risk of bias was assessed using the Effective Public Health Practice Project quality assessment tool. A descriptive synthesis approach was used for analysis. Twenty-two studies were included that reported medication- and/or firearm-storage behaviors and/or SDV after LMSC. Of the 19 studies assessing behavioral change, 14 reported a significant improvement in safe storage behaviors, and all studies measuring acceptability reported that participants found the interventions favorable. The quality of evidence was limited. No studies were rated low risk of bias, and 77% were rated high risk of bias. There was substantial heterogeneity in the settings, populations, injury prevention levels, delivery methods, and intervention elements. Many included studies focused on caregivers of pediatric populations, and few studies assessed SDV outcomes. Higher-quality trials conducted across a variety of settings, particularly those focusing on adults at risk of suicide, are needed. This review was preregistered with the International Prospective Register of Systematic Reviews (no. CRD42021230668).