HRV

This cross-sectional study examines associations among heart rate variability (HRV), emotional dysregulation, and parent-adolescent relationship quality in adolescents with Major Depressive Disorder (MDD). We hypothesize that lower HRV will be linked to greater emotional dysregulation and that more supportive parent-adolescent relationships will correlate with higher HRV. Participants will wear a Fitbit Charge 5 during nighttime sleep for 7 consecutive nights and complete validated measures of emotional regulation and relationship quality.