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.
Aged 12-18 years at the time of screening.
Current Major Depressive Disorder (MDD) documented in the electronic medical record by a licensed clinician; diagnosis verified using the Mental Health History - Parent Form.
Lives with a parent/legal guardian at least 50% of the time, confirmed on the Demographics Form.
Able and willing to provide assent, with a parent/legal guardian able and willing to provide informed consent.
Medical conditions affecting autonomic function or HRV (arrhythmia, congenital heart disease, cardiomyopathy, Type 1 or Type 2 diabetes, thyroid disorders, or moderate-to-severe sleep apnea), as reported on the Self-Administered Comorbidity Questionnaire.
Use of medications known to affect heart rate or HRV, including beta-blockers, calcium channel blockers, antiarrhythmics, tricyclic antidepressants, stimulants, or antipsychotics, as documented on the NIMH Concomitant Medication Log.
Active substance use, including nicotine/tobacco, alcohol, marijuana, recreational drugs, or energy drinks, as assessed by the Drug Use Screening Inventory.
Habitual high caffeine intake (>200 mg/day, equivalent to >4 cups of coffee or >2 cans of caffeinated soda per day), as assessed by a caffeine screening question during eligibility screening.