Teixeira de Almeida, M.; Quattrocchi, L.; Perroud, N.; Aboulafia Brakha, T.

This brief report presents circadian variation in salivary oxytocin levels in a sample of 58 female participants, including 35 healthy controls and 23 patients with borderline personality disorder (BPD). A significant increase in salivary oxytocin levels was observed between awakening and early afternoon (between 1 and 2 PM) (F = 20.54, p < 0.001, partial eta squared = 0.27, 99% achieved power). There were no significant group differences and no Group by Time interaction. These findings have implication for research in the field and suggest the need to control for time of assessment, as done in studies assessing cortisol.