Abstract
It is well-established that sleep and behavior are interrelated. Although studies have investigated this association, not many have evaluated the bidirectional relationship between the two. To our knowledge this is the first systematic review providing a comprehensive analysis of a reciprocal relationship between sleep and externalizing behavior. Five databases (PsycINFO, PubMed, Web of Science, Scopus, and Google Scholar) were utilized to yield a total of 3,762 studies of which 20 eligible studies, empirical articles examining bidirectionality of sleep and externalizing behavior, were selected for analysis. According to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis, the varying methodological approaches used in these studies were analyzed and synthesized, including examining differences and similarities in outcomes between distinct study designs (longitudinal vs cross-sectional), sleep measures (objective vs subjective vs a combination of both), informants (parents, self-report, teachers), and recruited participants (clinical, subclinical and typical populations). The assessment of risk of bias and quality of studies was guided by the instruments employed in research on sleep and behavior in the past. This review establishes that a bidirectional relationship between sleep problems and externalizing behavior clearly exists, and identifies limitations in the existing literature. Furthermore, the importance of early interventions that target both externalizing behaviors and sleep problems is highlighted as a potentially effective way of breaking the sleep-externalizing behavior relationship. Nonetheless, causality cannot be claimed until more trials that manipulate sleep and evaluate changes in externalizing behavior are conducted.