Abstract Introduction Cognitive control is a core regulatory process implicated in externalizing behaviors (e.g., anger, impulsivity), and it is typically measured by average accuracy. Less work has examined trial-to-trial variability, which may capture instability in control processes. Sleep is another key regulator of affect and behavior, yet its role in shaping links between cognitive control and externalizing behavior is not well understood. We tested whether cognitive control variability (CCV) and accuracy predicted two facets of externalizing behavior, anger and impulsivity, and whether sleep duration and efficiency moderated these associations. Methods Participants (N = 120; baseline, N = 89; 6-month; Mage = 21.7) were recruited across a spectrum of mental health symptoms. They completed two weeks of sleep monitoring via daily diary and actigraphy. Cognitive control was assessed with the Multi-Source Interference Task, from which two indices were derived: trial-to-trial variability in reaction time (CCV) and mean accuracy. Anger (past 7 days) and impulsivity (negative urgency) were assessed with self-report scales. Analyses tested whether sleep duration and efficiency moderated associations between CCV/accuracy and anger/impulsivity, covarying age, sex, mental health symptoms, and mean reaction time. Results For anger, higher CCV predicted greater symptoms, particularly when diary-based sleep duration was shorter (β=-0.08, p=.02). By 6 months, moderation effects diminished, but CCV continued to show direct associations with anger. For impulsivity, accuracy, not CCV, was the primary predictor. At baseline, actigraphy-based sleep efficiency moderated this link, such that higher efficiency increased the protective effect of accuracy. (β=--1.15, p=.01) By 6 months, higher accuracy predicted lower impulsivity across sleep indices. Sleep duration and efficiency showed no independent main effects. Conclusion Different aspects of cognitive control mapped onto distinct facets of externalizing. Variability in control signaled risk for anger, especially under shorter sleep, consistent with anger as a proximal, state-like outcome sensitive to short-term sleep and moment-to-moment instability. Accuracy was most relevant for impulsivity, aligning with impulsivity as a more trait-like disposition that is less tied to immediate sleep but is predicted by accuracy over time. Variability and accuracy thus index distinct pathways to externalizing, with sleep shaping how those pathways are expressed. Support (if any) R01MH124828
Griffith et al. (Fri,) studied this question.