Introduction to the special issue: sleep in pediatric medical populations.

Children and adolescents with acute and chronic medical conditions such as asthma, juvenile rheumatoid arthritis, and sickle cell disease (SCD) are reported to have more frequent and severe problems with sleep than their healthy peers (Passarelli et al., 2006; Yuksel et al., 2007). Multiple factors, including both acute and chronic pain (Palermo, 2000), underlying disease processes, concurrent medications, the impact of hospitalization, and comorbid psychiatric conditions such as depression and anxiety, are clearly important to consider in assessing the bi-directional relationship of sleep problems and acute and chronic illness in children (Lewin & Dahl, 1999). Sleep disorders that affect the quantity and quality of sleep can have salient effects on children’s daytime functioning, health, and well-being (Palermo & Kiska, 2005; Smaldone, Honig, & Byrne, 2007) as well as caregiver health and well-being (Meltzer & Mindell, 2006). Furthermore, the relationship between sleep problems and key physiologic parameters involved in health and disease, including the immune system and metabolic/endocrine regulation (Bryant, Trinder, & Curtis, 2004), highlights the importance of identifying and instituting appropriate interventions for sleep disorders in pediatric medical populations. There has been a recent surge in research on sleep in both adults and children with medical conditions. Theories about the connection between sleep and medical conditions are being developed to explain the bi-directional relationships among sleep problems and symptoms related to acute or chronic disease (Fiorentino & Ancoli-Israel, 2007; Lewin&Dahl, 1999). Despite this increased research focus, there is a multitude of challenges investigators face in conducting this research. One particular challenge is that sleep is a broad domain encompassing behaviors, patterns, and problems or disorders. Several subjective and objective measures, including self-report questionnaires, actigraphy, and polysomnography (PSG) are available to assess different aspects of sleep across the developmental age span. As demonstrated in this issue, these methods are associated with their own unique advantages and disadvantages. A second challenge is that in the context of disease, a range of potential influencing factors both within the child and the child’s environment may contribute to sleep patterns and behaviors and need to be identified. The purpose of the Special Issue of the Journal of Pediatric Psychology on Sleep in Pediatric Medical Populations is to spotlight current research on sleep of children with acute and chronic medical conditions and their caregivers using the best available methods. Ultimately, we are most interested in understanding the impact of sleep on important health-related outcomes, with a goal of informing prevention and treatment of sleep disruption in children with medical conditions or health risks.