Vagally-mediated heart rate variability during an emotionally arousing paradigm in adolescents with major depressive disorder

Major depressive disorder (MDD) in adolescence is associated with impaired emotion regulation and altered autonomic functioning, particularly reduced cardiovagal control indexed by heart rate variability (HRV) as a non-invasive marker of vagal modulation. However, the conventional linear indices may insufficiently capture the complexity of autonomic regulation, therefore integrating linear and nonlinear HRV measures during emotional challenges might improve objective identification of adolescent depression. We have evaluated 70 drug-naïve patients with MDD (average age: 15.3 ± 1.6 years) and 70 age- and sex-matched healthy controls (average age: 15.5 ± 1.6 years). Short-term HRV was recorded during an emotion-evoked paradigm consisting of baseline, positive and negative visual stimuli, and recovery periods. Selected linear and nonlinear vagally-mediated HRV indices were analysed. Across all protocol periods, adolescents with MDD showed significantly shortened RR intervals and reduced vagally-mediated HRV indices ( p ≤ 0.05 – p < 0.001) compared to controls. Receiver Operating Characteristic analysis demonstrated moderate diagnostic accuracy for individual parameters (Area Under Curve (AUC) = 0.624–0.846), whereas combining linear and nonlinear indices markedly improved discrimination. The best diagnostic performance was achieved using all HRV parameters within the whole protocol (AUC = 0.973), with separate sex-stratified analyses showing perfect discrimination for both girls and boys (AUC = 1.000). Adolescents with MDD are characterized by reduced cardiovagal control at rest and during emotional processing. Integrating linear and nonlinear HRV features, particularly under emotion-evoked conditions, provides excellent discrimination between adolescents with MDD and healthy adolescents. Vagally-mediated HRV thus represents a promising objective biomarker for the early identification of adolescents with MDD. • Adolescents with MDD show markedly reduced cardiovagal control. • Combining linear and nonlinear HRV indices improves identification of adolescents with MDD. • Emotion-evoked HRV provides stronger discrimination than resting measures alone. • Excellent MDD discrimination using the composite index within the emotion-evoked paradigm