Eating disorder (ED) symptoms often co-occur with non-suicidal self-injury (NSSI). This comorbidity is consistent with evidence that trait negative urgency increases risk for both of these phenomena. We previously found that impaired late-stage negative emotional response inhibition (i.e., negative emotional action termination or NEAT) might represent a neurocognitive mechanism for heightened negative urgency among people with NSSI history. The current study evaluated whether relations between negative urgency and ED symptoms similarly reflect deficits in this neurocognitive process. A total of 105 community adults completed an assessment of ED symptoms, negative urgency, and an emotional response inhibition task. Results indicated that, contrary to predictions, negative urgency and NEAT contributed independent variance to the prediction of ED symptoms, while controlling for demographic covariates and NSSI history. Worse NEAT was also uniquely associated with restrictive eating, after accounting for negative urgency. Our findings suggest that difficulty inhibiting ongoing motor responses triggered by negative emotional reactions (i.e., NEAT) may be a shared neurocognitive characteristic of ED symptoms and NSSI. However, negative urgency and NEAT dysfunction capture separate variance in the prediction of ED-related cognitions and behaviors, distinct from the pattern of results we previously observed in NSSI.Brain Sci. 2020, 10, 104 2 of 17 of diverse self-injurious behaviors [12][13][14][15][16] and a putative non-specific marker of general vulnerability for psychopathology [17,18]. Consistent with this notion, the most commonly reported function of NSSI and ED behaviors is to reduce negative affect [19][20][21][22][23][24][25]. Ecological momentary assessment corroborates the idea that direct and indirect self-injury are both motivated by a desire to alleviate unpleasant emotional states, as increased negative affect proximally predicts episodes of NSSI, dysregulated eating, and compensatory behaviors [26][27][28][29][30][31][32].Much like emotion dysregulation, impulsivity is implicated in various psychiatric disorders and self-injurious behaviors. This multifaceted construct encompasses several subfactors, including impulsive personality traits and impulsive behavior, or motor impulsivity. Impulsive behavior can be further divided into impulsive action and impulsive choice, which reflect inhibitory control and decision-making deficits, respectively. Impaired inhibitory control and consequently, impulsive action, are aspects of altered neurocognition broadly involved in suicidal thoughts and behaviors [12]. Impulsive personality traits, especially negative urgency, are also associated with NSSI [11,[33][34][35][36] and dysregulated eating [36][37][38][39][40]. Negative urgency is a transdiagnostic personality characteristic that refers to individual differences in the tendency to act impulsively in response to negative affect [41]. Heightened negative urgency among people who engage in self-injurious behaviors s...