Identification of adolescent patients with depression via assessment of the niacin skin flushing response.

Background: Depressive disorder (DD) affects approximately 20 % of adolescents worldwide, but it is underdiagnosed due to the lack of objective biomarkers. Niacin skin flushing response (NSFR) is an objective and noninvasive biomarker of adult depression; however, its effectiveness has not been assessed in adolescents.

Methods: This study included 198 adolescents with 50 % healthy controls (HC). Linear mixed-effects model and multiple linear regression analyses were performed to assess differences in NSFR between the DD and HC groups. Logistic regression models based on NSFR were constructed, and the area under curve (AUC) was calculated to evaluate the performance of models. Spearman correlations were calculated to assess the relationships between NSFR and disease duration and hormone levels associated with puberty.

Results: Adolescents with DD displayed significantly attenuated and delayed NSFR compared to HC. NSFR effectively distinguished DD patients from HC with AUC values of 0.719 (sensitivity = 0.844) and 0.721 (sensitivity = 0.829) determined in the discovery and validation sets, respectively. Within the DD group, the maximum degree of NSFR was negatively correlated with the disease duration (r = -0.28, p = 0.011), and the overall degree of NSFR was positively associated with prolactin (r = 0.29, p = 0.039) and thyroxine (r = 0.29, p = 0.027) levels.

Limitations: Future investigations will be necessary to confirm our results in an independent sample set.

Conclusions: This study provides the first evidence of the utility of NSFR as an objective auxiliary diagnostic biomarker for adolescent depression. It provides new clues to understand the pathophysiology of the disease, and helps promote precise diagnosis, treatment, and prognostic evaluation of adolescent depression.