Daily mood and sleep: reciprocal relations and links with adjustment problems.

Children's sleep problems are common and associated with increased risk for adjustment problems. We examined daily links between children's sleep and mood, using a daily diary method and actigraphy. We also tested children's daily mood as a mediator of relations among sleep and children's broader internalizing and externalizing symptoms. A community sample of 142 children (mean age = 10.69 years; 57% girls; 69% European American, 31% African American) and their parents participated. For 1 week, children wore actigraphs and parents completed a daily telephone interview about their child's mood. Following the week of actigraphy, mothers and fathers reported on their child's adjustment. Multi-level models indicated within-person relations between children's mood and subsequent sleep fragmentation (indicated by increased activity) and sleep latency, and between-person relations between sleep latency and subsequent mood on the next day. Significant indirect effects were found such that a more negative daily mood (aggregated across diary days) mediated relations between poor sleep efficiency and longer sleep latency and parent-reported internalizing and externalizing symptoms. Findings extend previous research by highlighting disruptions to children's daily mood as a potential mechanism linking sleep problems to children's mental health.