Firearms are the leading cause of death in US suicides and account for more than 60% of military suicides. A primary driver of these high rates appears to be ready access to firearms. Research suggests that firearm suicides could potentially be reduced by reducing and/or limiting access to firearms. Considering these data, lethal means counseling (LMC) is a recommended best practice for suicide prevention (e.g., National Action Alliance for Suicide Prevention). Results of a recently completed Department of Defense-sponsored randomized control trial (RCT) conducted by the investigators showed that safe firearm storage practices (i.e., use of locking devices and/or safes) could be increased among Servicemembers using a brief lethal means counseling (LMC) protocol developed in part by the investigators. Though superior to control, 45% of Servicemembers who received LMC still maintained at least one unsafely stored firearm, suggesting they continued to experience barriers to behavior change. Accumulating evidence suggests that fear of the unknown-a form of anxiety commonly experienced by people with low tolerance for uncertainty-may be an important barrier to safe firearm storage. The primary aim of Project 5 is to test a brief modular intervention to improve the effectiveness of LMC on safe firearm storage practices among firearm-owning Servicemembers. In this study, the investigators will examine if LMC's effects on firearm storage practices can be enhanced among Servicemembers who first receive an intervention designed to reduce their intolerance of uncertainty (IU). These results could provide important information about how LMC can be most effectively delivered to an especially high risk subgroup of firearm-owning Servicemembers.

F1.1. Firearm Acquisition and Storage as a Strategy to Cope with Fear of the Unknown. The coping model of protective gun ownership posits that people acquire firearms to reduce distress experienced from inflated perceptions of environmental threat, and are unlikely to safely store firearms because doing so is perceived to inhibit readiness to respond to unexpected and uncertain threats. Firearm owners who acquire firearms for the primary purpose of self-protection (i.e., protective firearm owners) report overgeneralized perceptions of the world and other people as dangerous and/or threatening. Among firearm owners, exaggerated threat perceptions are also associated with the intention to acquire additional firearms. Negative affect is significantly higher among firearm owners who use no safe storage practices (F(1,872)=6.9, p=.009). Anxiety about the unknown may therefore serve as a barrier to safe firearm storage and decrease the effectiveness of LMC. The investigators will test this hypothesis by testing the impact of a brief intervention designed to reduce IU when delivered to firearm-owning Servicemembers.

F1.2. Intolerance of Uncertainty as a Risk Factor for Anxiety and Unsafe Firearm Storage. IU involves an aversion to ambiguity and increased distress when experiencing uncertainty. Elevated IU amplifies the experience of stress and anxiety, causing people to engage in maladaptive cognitive and behavioral strategies to reduce distress. It is posited that IU may impact a Servicemember's perception of threat from the environment and that this heightened threat perception will limit their desire for safe storage practices. This is supported by a recent study by the investigators in which IU and exaggerated threat expectancy were significantly higher among adults intending to acquire a firearm as compared to those who were not (partial η2=.014-.017). Among Servicemembers with elevated IU, adoption of safe firearm storage practices may therefore be enhanced if IU is first reduced. This hypothesis will be tested in the current study using an empirically-supported, brief web-based intervention. The use of a web-based intervention platform significantly improves the potential scale and reach of the intervention.

F1.3. Targeting IU to Enhance Lethal Means Counseling (LMC). IU is an ideal construct to target in a web-based intervention given the abundance of research finding elevations in IU across a broad spectrum of suicide risk factors. For example, IU is a strong transdiagnostic correlate of many psychological and behavioral disorders associated with increased risk for suicide: generalized anxiety disorder, major depression, obsessive compulsive disorder, social anxiety disorder, panic disorder and agoraphobia, substance use disorders, eating disorders, and posttraumatic stress disorder. Other studies have implicated IU as a risk factor for suicidal thoughts and behaviors. IU is malleable, even in very brief interventions. In a recent study, the investigators conducted the only RCT of a CBT-based intervention for IU. In that study, an in-person IU Treatment (IUT) comprised of psychoeducation and cognitive reappraisal techniques was compared to a control condition focused on psychoeducation about health lifestyle behaviors. IUT led to significantly larger reductions in IU, anxiety, and depression during follow-up, indicating IU can be reduced with a brief intervention. Results of that study also showed that the majority of participants found the intervention easy to understand, helpful, and applicable to their daily lives.

F1.4. IUT Refinement. Since completing this first RCT, this intervention has been refined to improve the intervention. When modifying interventions, it is critical to involve relevant stakeholders in the process. Two key alterations to IUT include a web-based delivery and augmenting IUT with a mobile app for ecological momentary assessment (EMA) and ecological momentary intervention (EMI). EMI is ideal for these brief interventions because it allows for participants to gain much-needed practice of challenging negative automatic thoughts and completing behavioral experiments in real-time, thereby improving internalization of learned skills and strategies. The investigators recently completed a focus group with 8 people (M age = 33.13, standard deviation \[SD\] = 11.50; 62.5% female) reporting IU at least 1 SD above the community mean (M = 43.75, SD = 7.5). Participants reported the content was accessible, easily understood, and highly relevant to their distress. Participants thought inclusion of EMA and EMI would improve participant engagement and reported they would not perceive completion of multiple surveys daily to be a burden. Participants also believed that personalized content would increase engagement. Finally, participants assisted in identifying exemplar behavioral experiments and in refining a delivery mechanism as successful completion of behavioral experiments is a core driver in anxiety-based CBT interventions. Similar augmentations to brief interventions for stress (d = .5), generalized anxiety disorder (ds = .4-.6), and panic disorder (d = .5) have been successful in enhancing intervention effects, further underscoring the promise of including EMI to optimize outcomes.

F1.5. Summary. In a recently completed RCT, the investigators showed that LMC increases firearm storage practices among firearm-owning Servicemembers. Despite these promising results, nearly half of Servicemembers did not fully adopt safe firearm storage practices. Subsequent research suggests that exaggerated perceptions of the world as a dangerous and threatening place may be a barrier to these practices. This study is designed to determine if a brief intervention that has been shown to reduce IU-a cognitive bias that increases threat perceptions and anxiety-can increase the effectiveness of LMC. This project will be the first to test a brief modular intervention to improve LMC as a preventative intervention for suicide. These results could inform community-based suicide prevention efforts in the DoD and may also improve the effectiveness of LMC delivered within healthcare settings.