Attenuated niacin skin flushing response in children and adolescents with mental disorders: A transdiagnostic early warning marker.

Mental disorders are the leading cause of disability in children and adolescents worldwide, but among the difficulties that pediatric mental health faces is a lack of objective biomarkers used for early identification or diagnosis. Studies to date indicate that niacin skin flushing response (NSFR) could be a biomarker for adult patients with schizophrenia and affective disorders. However, there are limited data on NSFR in pediatric patients with mental disorders. This study provides the first evidence of NSFR as a potential transdiagnostic marker in pediatric patients with schizophrenia (SZ), bipolar disorder (BD), depressive disorder (DD) and autism spectrum disorder (ASD). We conducted 10-min niacin skin flush tests on 227 pediatric participants, including 59 SZ patients, 23 BD patients, 57 DD patients, 40 ASD patients and 48 healthy controls (HCs). Group, time and the concentrations of aqueous methyl nicotinate had significant effects on the flush scores. Pediatric patients with BD, DD, and SZ clustered together, while ASD patients appeared to be more similar with HCs. SZ, BD and DD groups had lower flush scores than HCs, while ASD group had higher scores than BD and DD groups. These findings suggested NSFR was blunted in pediatric SZ, BD and DD and was distinct in ASD from the other disease groups. Our data demonstrate NSFR could be a transdiagnostic marker for pediatric SZ, BD and DD, which would help to identify a subgroup of patients sharing dysfunctions of membrane phospholipids. Besides, NSFR might have potential for early identification of affective disorders from ASD.