Biomarker

Alteration in Anxiety Disorders

Underlying Biological Process

Heart Rate Variability (HRV)

HRV is lower [39].

Autonomic dysfunction is evident, with diminished vagal tone and increased sympathetic dominance [39].

Cortisol

Cortisol levels are abnormally high [40].

The HPA (Hypothalamic-Pituitary-Adrenal) axis is dysregulated, resulting in prolonged cortisol release and heightened stress sensitivity [40].

Alpha-Amylase

Alpha-amylase production is elevated [41].

The sympathetic-adrenal-medullary (SAM) system is overly activated, contributing to excessive stress reactivity [41].

Brain-Derived Neurotrophic Factor (BDNF)

BDNF levels are significantly reduced [43].

Insufficient neurotrophic support affects synaptic plasticity, reducing resilience to stress-related disorders [43].

Interleukin-6 (IL-6)

IL-6 concentrations are high [45].

Increased activity of pro-inflammatory cytokines contributes to neuroinflammation and emotional instability [45].

C-Reactive Protein (CRP)

CRP levels are elevated [41].

Systemic inflammation persists, exacerbating the body's stress response and altering neural functions [41].

Amygdala Activity

The amygdala shows excessive activation [44].

Excessive excitatory signaling and weak regulatory inhibition cause the amygdala to remain hyperactive [44].

Hippocampal Structure

The hippocampus shows reduced volume [45].

Chronic stress exposure leads to structural degradation in the hippocampus, contributing to impaired cognitive and emotional processing, which affects memory function and the brain ability to regulate stress [45].