Mechanisms underlying the association of firearm availability and vulnerability to suicide

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ABSTRACT The U.S. general population suicide rate has increased by more than 35% over the past 20 years. Firearm suicides have risen by 15% during this same timeframe, and account for the majority of U.S. suicides and nearly two-thirds of all firearm-related deaths. Firearm availability contributes to suicide mortality in part by increasing the probability of a fatal outcome following suicidal behavior. Firearm availability may also contribute to suicide mortality indirectly through its influence on anticipatory anxiety and cognitive control, two biobehavioral processes that can increase vulnerability to suicidal behaviors. Our primary objective is to identify candidate targets for interventions and programs intended to prevent firearm suicide. To achieve this objective, we will enroll three target groups, half of whom will have a history of suicide ideation: (a) handgun owners who regularly carry a firearm, (b) handgun owners who do not regularly carry a firearm, and (c) non- gun owners. We will then compare these groups on a variety of self-report, psychophysiological, behavioral, and ecological assessment methods. We will (Aim 1) reveal biobehavioral processes associated with firearm availability and suicide risk using the NPU-threat startle paradigm and the stop-signal reaction time test to identify differences in behavioral reactivity under conditions of uncertain threat (i.e., anticipatory anxiety) and differences in inhibitory control. We hypothesize that handgun owners and subjects with a history of suicide ideation will be associated with increased anticipatory anxiety and decreased inhibitory control. We will (Aim 2) examine associations among firearm possession, emotional reactivity, and suicide risk following socially ambiguous situations using the Video Social Emotional Information Processing (V-SEIP) task to assess differences in negative emotional reactivity during socially ambiguous situations. We hypothesize that subjects who imagine they are in possession of a firearm will show increased emotional reactivity during socially ambiguous situations. We will (Aim 3) identify contextual factors that influence emotional reactivity among handgun owners using ecological momentary assessment (EMA). We hypothesize that handgun owners and subjects with a history of suicide ideation will show more variability in negative mood state. We further hypothesize that variability in negative mood state will be increased when a subject is in possession of a firearm. The proposed project will provide novel information about developmental, individual, and contextual factors that contribute to firearm suicide, and will identify potential intervention targets that could be strengthened to reduce the risk associated with firearm availability. This research will also inform subsequent studies that will rigorously investigate the firearm-suicide correlation. Finally, our results could reveal new clues for improving the effectiveness of firearm injury and mortality prevention programs.