Acute Overarousal and the Acquired Capability for Suicide

Converging evidence suggests that acute states of overarousal (namely, agitation, insomnia, and nightmares) are commonly observed prior to near-lethal or lethal suicidal behavior. Yet, there has been very little research evaluating theory-driven explanations of these phenomena. The intention of the proposed project was to address this gap in the literature by drawing from and extending the tenets of the interpersonal theory of suicide (Joiner, 2005; Van Orden et al., 2010), which suggests that most individuals will be discouraged from engaging in suicidal behavior because of its fearsome nature. For most individuals, the prospect of engaging in potentially lethal suicidal behavior will elicit some degree of arousal. We expected that the effect of arousal would be particularly relevant, however, when considered in the context of the acquired capability for suicide. A total of 191 participants were randomized to an arousal induction (500-mg caffeine) or placebo control condition. All participants then engaged in a behavioral approach task designed as a proxy for suicidal behavior, which involves assessing approach motivation toward a potential lethal stimulus. Main analyses examined the independent and joint effects of acquired capability and arousal on approach motivation. Secondary analyses considered whether the effects would be better understood in the context of factors thought to contribute to suicidal desire. The influence of depressive symptoms on the relationship between arousal and suicidal behavior as well as the effects of arousal on pain tolerance were also examined within exploratory analyses. Results were partially in line with expectations. Findings are considered within the context of the broader literature, providing insight on directions for future research further elaborating our understanding of the nature of the relationship between overarousal and suicidal behavior.