Study design and protocol for a randomized clinical trial investigating a brief fear of uncertainty-focused intervention as an adjunct to project safe guard for military personnel.

Background: In the United States (US), the proportion of firearm suicide deaths are higher among military personnel compared to the general population. Secure firearm storage practices (e.g., gun safe, unloaded) can reduce the risk of firearm suicide. A randomized controlled trial, called Project Safe Guard (PSG) found that providing lethal means counseling (LMC) to firearm-owning service members increased secure firearm storage practices; however, some still stored at least one firearm unsecurely. Intolerance of uncertainty (IU) may be a barrier to secure firearm storage that decreases the effectiveness of LMC. This study will examine the impact of a brief intervention that targets IU (i.e., Cognitive behavioral therapy for Uncertainty Enhanced; CUE) on improving the effectiveness of PSG-LMC on secure firearm storage practices among firearm-owning service members. In this protocol paper, we describe the rationale and methodology for this study. Methods: This study uses a counterbalanced design with two conditions to test the acceptability, feasibility, and potential efficacy of both interventions with 100 current or recently discharged service members who report elevated IU and storing at least one firearm unsecurely. Participants are randomized to either receive CUE or PSG-LMC first, and then receive the second intervention approximately two weeks later. Participants will complete a baseline assessment, ecological momentary assessment (EMA) via their mobile devices, and follow-ups at 1-, 3-, 6-, 9-, and 12-months post-baseline. All interventions will be delivered remotely. Conclusions: This study aims to inform how to improve firearm safety in military personnel with elevated IU.