Validation of the Self-Rating of Biological Rhythm Disorder for Adolescents (SBRDA) Scale by Dim Light Melatonin Onset in Healthy Young Adults

Understanding the biological rhythms that influence young adult health is vital because the combination of biological changes and a circadian phase delay lead to young adults being at high risk of circadian misalignment. We have previously established a self-rating of biological rhythm disorder for adolescents (SBRDA). However, we did not externally validate the SBRDA against objective measures of biological rhythms such as dim light melatonin onset (DLMO)-the gold standard of the endogenous circadian phase. The purpose of this study was to verify the effectiveness of SBRDA in identifying individuals with biological rhythm disorders. Our participants were 42 (47.2%) boys and 47 (52.8%) girls with an average age of 18.5 ± 1.2 years. Saliva samples were collected from 4 h before bed time to 2 h after sleep every 60 min in a dim-light (<50 lx) laboratory environment. Biological rhythm parameters were assessed using questionnaires, including SBRDA, MEQ, and MCTQ. The mean DLMO time (h) was 22.2 ± 1.9. The DLMO correlated significantly with the SBRDA score (r = 0.33, p < 0.001), MEQ score (r = -0.24, p < 0.05), and MSFsc (r = 0.26, p < 0.05). ROC curve analysis showed that SBRDA was of diagnostic value for biological rhythm disorder (p < 0.05). Our observations demonstrate that SBRDA, which is consistent with MEQ and MCTQ, can be used to reflect endogenous circadian rhythm disorders in young adults. Exposure to dim light may activate melatonin secretion and lead to an earlier peak in young adults with biological rhythm disorder.