Respiratory sinus arrhythmia and adaptive emotion regulation as predictors of nonsuicidal self-injury in young adults.

Research suggests that both respiratory sinus arrhythmia (RSA) and emotion regulation are related to maladaptive outcomes. However, little is known about how these factors jointly contribute to nonsuicidal self-injury (NSSI). We examined how resting RSA and RSA withdrawal to stress predicted NSSI among young adults, and whether adaptive emotion regulation strategies moderated this effect. We examined this relation in a sample of 70 young adults (M = 19.25, SD = 0.92, 94% female), 35 with a recent history of NSSI and 35 who had never engaged in NSSI. Participants completed a baseline questionnaire and lab visit where physiological responses to a social stressor were collected. Results indicated that resting RSA did not predict recent NSSI engagement. However, greater RSA withdrawal to social stress significantly predicted recent NSSI (β = 1.35 [0.57], Wald χ = 5.52 p = 0.02). Further, problem-solving moderated the relation between RSA withdrawal and recent NSSI such that individuals with greater levels of RSA withdrawal were significantly more likely to engage in NSSI if they also reported low problem-solving (β = -1.44 [0.64], Wald χ = 5.16, p = 0.02). In contrast, the effect of greater RSA withdrawal on NSSI was buffered by high problem-solving. Cognitive reappraisal did not moderate the relation between RSA withdrawal and NSSI. These findings suggest that problem-solving may be an important moderator in the relation between physiological reactivity and NSSI. Interventions should help clients with poor self-regulation develop adaptive problem-solving strategies.