Relationship between the fecal microbiota and depression and anxiety in pediatric patients with orthostatic intolerance

Objective: Orthostatic intolerance (OI) is an important health problem for children and adolescents. The onset and exacerbation of OI are strongly affected by psychosocial factors. Intestinal microbial deviations, which are affected by food and lifestyle factors, are an important risk factor for adult psychiatry patients, but their roles in pediatric patients are unclear. The objective of this study was to investigate the intestinal microbiota and its involvement in the mental health of children with OI. Methods: Fifty-six fecal samples from pediatric OI patients and 9 samples from healthy children were examined with terminal-restriction fragment length polymorphism analysis from July 2016 to January 2018 at Nihon University Itabashi Hospital, Tokyo, Japan. Bacterial diversity was analyzed using the Shannon-Wiener index and the Simpson index. All OI patients were assessed using 2 different psychological scales: the Children’s Depression Inventory and the Children’s Manifest Anxiety Scale. The patients were then divided into the following subgroups: depression or nondepression and anxiety or nonanxiety. Results: The mean proportion of Clostridium subcluster XIVa and/or Enterobacteriaceae (operational taxonomic unit [OTU] 940) in the OI patients was significantly higher than that in the healthy controls (P = .02). Among OI patients, Bifidobacterium (OTU 124) was less frequent in the depression group than in the nondepression group. However, depression and anxiety showed no correlation with bacterial diversity. Conclusions: Pediatric OI patients showed deviations in the intestinal bacterial flora. The intestinal flora can serve as a novel therapeutic target for the mental health management of intractable pediatric OI patients.