“…Two primary theories shed light on why family instability and transitions may have deleterious consequences for adolescent socioemotional and behavioral outcomes at age 15 (including internalizing behaviors, externalizing behaviors, depressive symptoms, anxiety, delinquency, and exclusionary school discipline): family stress theory and family boundary ambiguity theory. Family stress theory focuses on the stress associated with transitions, which can affect parental mental health, parenting quality, parent–child relationships, and family resources such as money or time (Arditti, ; Fomby & Osborne, ; McCubbin & Patterson, ; Umberson, Williams, Powers, Liu, & Needham, ; for a summary, see Malia, ). Research documents that parental relationship transitions are associated with more mental health struggles, lower parenting quality, strained parent–child relationships, and more limited family economic resources.…”