Reciprocal processes linking marital conflict and sibling relationship challenges during the COVID-19 pandemic.

During times of stress, families are tasked with maintaining or reestablishing a state of equilibrium in order to cope with stress on the family system. The pandemic context represents an opportunity to study the interdependencies between family members and relationships under duress. The present study examined the transactional effects linking the marital and sibling subsystems throughout the early months of the pandemic. It was hypothesized that more marital conflict would predict more sibling relationship challenges, and vice versa, across the pandemic and that COVID-19 stress would moderate this relationship. Participants included 505 caregivers who reported on two children (sibling dyads) in the home at four time points (T1: May 2020; T2: July 2020; T3: September 2020; T4: November 2020). Caregivers reported on pandemic-related stress at T1, and marital conflict and sibling relationship challenges (conflict and lack of support) at T1-T4. Using a four-wave random-intercept cross-lagged panel model, results showed that, on average, more marital conflict was related to more sibling relationship challenges (p < .001). However, negative cross-lagged effects linked marital and sibling relationship challenges throughout the pandemic, such that greater sibling challenges at T1 predicted less marital conflict at T2 (p = .04), which in turn predicted greater sibling relationship challenges at T3 (p = .03). Degree of pandemic-related stress did not moderate the cross-lagged effects between marital conflict and sibling relationship challenges (p = .22). Differential mechanisms linking sibling and marital functioning may account for stable between-family differences (i.e., spillover) as compared with within-family fluctuations over time (i.e., compensation). (PsycInfo Database Record (c) 2025 APA, all rights reserved).