Sleepless nights, sour moods: daily sleep-irritability links in a pediatric clinical sample

Background: Sleep, or a lack thereof, is strongly related to mood dysregulation. Although considerable research uses symptom scales to examine this relation, few studies use longitudinal, real-time methods focused on pediatric irritability. This study leveraged an ecological momentary assessment (EMA) protocol, assessing bidirectional associations between momentary irritability symptoms and daily sleep duration in a transdiagnostic pediatric sample enriched for irritability. Methods: A total of N = 125 youth (M_age = 12.58 years, SD = 2.56 years; 74% male; 68.8% White) completed digital, in vivo surveys three times a day for 7 days. For a subset of youth, their parents also completed the EMA protocol. Trait irritability was measured using youth-, parent-, and clinician-report to test its potential moderating effect on the association between sleep duration and momentary irritability. Results: Results from multilevel modeling dynamically linked sleep to irritability. Specifically, according to youth- and parent-report, decreased sleep duration was associated with increased morning irritability (bs ≤ −.09, ps <.049). A bidirectional association between parent-reported nightly sleep duration and anger was found—increased evening anger related to decreased nightly sleep duration, and decreased sleep duration related to increased morning anger (bs ≤ −.17, ps <.019). Trait irritability moderated this association, which was stronger for more irritable youth (b = −.03, p <.027). Conclusions: This study adds to the literature and suggests sleep-irritability dynamics as a potential treatment target.