Parasympathetic predominance is a risk factor for future depression: A prospective cohort study

Area of Science:

• Gerontology
• Cardiology
• Psychiatry

Background:

• Autonomic nervous system (ANS) activity, particularly parasympathetic function, is linked to depression.
• The causal relationship between parasympathetic changes and depression remains unclear; they may be a cause or a protective response.

Purpose of the Study:

• To investigate the association between autonomic nervous system activity and depression risk in older adults.
• To determine if heart rate variability (HRV) measures predict future depression in euthymic and subsyndromal depressed individuals.

Main Methods:

• Longitudinal cohort study with 464 baseline participants and 253 at 5-year follow-up.
• Heart rate variability (HRV) analysis using 5-minute ECG recordings in individuals aged 65+.
• Linear and logistic regression models assessed HRV associations with Geriatric Depression Scale (GDS) scores and risk of subsyndromal depression (SSD).

Main Results:

• Baseline HRV measures (low-frequency power, high-frequency power, LFN/HFN ratio) correlated with 5-year follow-up GDS scores, but not baseline GDS.
• Elevated high-frequency power (HFN) at baseline significantly predicted increased depression risk at 5-year follow-up in euthymic subjects (OR = 3.025).

Conclusions:

• Parasympathetic predominance, indicated by higher HFN, may precede the development of depression in older adults.
• These findings suggest a potential predictive role for HRV in identifying older adults at risk for depression.