Diurnal changes of salivary oxytocin in healthy and psychiatric adolescents

Oxytocin, a neuropeptide with implications for interpersonal relationships and psychopathology, remains relatively unexplored in adolescence, particularly in acute mental health states. While studies examined baseline levels and reactivity patterns in salivary oxytocin, no study has tested diurnal patterns of oxytocin in the context of youth mental health. The current study examines diurnal rhythms of salivary oxytocin in 34 adolescent patients admitted to a psychiatric inpatient ward, as compared to 33 healthy peers. Samples were collected at four daily time-points across two consecutive days (8 a.m., 12 p.m., 4 p.m., 8 p.m.). Patients underwent psychiatric assessments and completed self-report questionnaires prior to the study and again at discharge. Results revealed significant differences between patients and healthy controls, indicating elevated overall salivary oxytocin production in the patient group. No significant differences were found among patients at the admission and discharge sampling. A consistent diurnal pattern emerged across participants that showed oxytocin elevation toward evening. Diurnal oxytocin levels correlated with measures of emotion regulation and anxiety. Findings are the first to describe the diurnal rhythms of oxytocin in youth and suggest that diurnal oxytocin may serve as additional biomarker of psychopathology. Future research is needed to assess processes that may lead to change in patients' diurnal oxytocin patterns.