The objective of this study was to develop a pediatric measure of chronic nausea severity, the Nausea Severity Scale (NSS), and evaluate its reliability and validity in youth with abdominal pain-related functional gastrointestinal disorders (AP-FGID). Pediatric patients (aged 11⁻17 years-old, n = 236) presenting to an outpatient clinic for evaluation of abdominal pain completed the NSS, Children's Somatization Inventory (CSI), Functional Disability Inventory (FDI), Abdominal Pain Index (API), Patient-Report Outcomes Measurement Information System (PROMIS), Anxiety and Depression Scales and the Pediatric Rome III Questionnaire for FGIDs. The NSS demonstrated good concurrent, discriminant, and construct validity, as well as good internal consistency. One-third (34%) of AP-FGID patients reported experiencing nausea "most" or "every day" in the previous two weeks. The severity of nausea was higher in females than males and correlated significantly with the severity of somatic symptoms, functional disability, anxiety, and depression. The NSS is a valid and reliable measure of nausea in children with AP-FGID.
Keywords: chronic nausea; functional abdominal pain; nausea severity scale.