Stress and anxiety are prevalent conditions with significant personal and societal burden. This study evaluated the effects of non-invasive vagus nerve stimulation (nVNS) on anxiety severity in individuals with moderate to severe anxiety symptoms.

Thirty-eight participants were recruited from a pool of 220 applicants, selected based on GAD-7 scores ≥9 and Zung Anxiety Scale scores ≥50. Participants used an auricular nVNS device daily for 60 minutes over a 4-week period. Anxiety symptoms were assessed biweekly using the GAD-7 scale.

Both the GAD-7 and Zung scales were used to capture different dimensions of anxiety. The GAD-7 focuses on core clinical symptoms, while the Zung scale includes broader physical and emotional aspects. Using both provides a more complete and reliable picture of patient improvement.

Results showed a 54% reduction in GAD-7 scores at 4 weeks, with average severity improving from severe to mild within 2 weeks. At 6-month follow-up, 73% of participants reported continued use of the device at least 3 times weekly. These findings suggest nVNS is a promising alternative for anxiety reduction with sustained adherence.

Anxiety disorders are among the most common mental health conditions globally, contributing to impaired quality of life, reduced productivity, and increased healthcare costs. Traditional treatments, including pharmacotherapy and psychotherapy, may be associated with side effects, limited access, or variable efficacy.The vagus nerve plays a central role in autonomic regulation and emotional processing.

Non-invasive vagus nerve stimulation (nVNS), delivered through auricular branches, has emerged as a potential intervention for modulating parasympathetic activity and reducing anxiety symptoms. Preliminary evidence indicates that nVNS can alter neural circuits related to stress regulation, improve heart rate variability, and enhance resilience to stressors.This study aimed to evaluate the efficacy of daily nVNS on anxiety symptoms over a 4-week intervention period in individuals with moderate to severe anxiety.

Participants:
⦁ Applicants: 220
⦁ Inclusion: GAD-7 ≥9 and Zung Anxiety Scale ≥50
⦁ Final sample: 37 subjects (moderate–severe anxiety at baseline)

Intervention:
⦁ Device: Non-invasive vagus nerve stimulator (Roga device)
⦁ Protocol: 60 minutes daily, for 4 consecutive weeks

Assessments:
⦁ Generalized Anxiety Disorder 7-item (GAD-7) scale
⦁ GAD-7 Scale:
0-4: Minimal Anxiety
5-9: Mild Anxiety
10-14: Moderate Anxiety
15-21: Severe Anxiety
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⦁ Zung Anxiety Scale 20-item (ZUNG-20) scale
⦁ Zung-20 Scale:
20–44: Normal Range
45–59: Mild to Moderate Anxiety Levels
60–74: Marked to Severe Anxiety Levels
75 and above: Extreme Anxiety Levels

⦁ Measurements: Scales measured at baseline, week 2, and week 4

⦁ Retention: Follow-up at 6 months, self-reported device usage frequency

Design:
⦁ Prospective, single-arm, open-label user study
⦁ Retention: Follow-up at 6 months, self-reported device usage frequency

Design:
⦁ Prospective, single-arm, open-label user study

The effects of nVNS use were evaluated over a 4-week period using validated anxiety scales. Both self-reported measures showed substantial reductions in symptoms, with the greatest improvements occurring in the first 2 weeks and additional gains sustained through week 4.

GAD-7 scores started at 15 (severe range) (Fig. A). By week 2, scores dropped to 9, a 41% reduction, indicating a shift from severe to mild anxiety. By week 4, scores further declined to 7, representing a 54% total reduction from baseline and placing patients in a much lower anxiety range.

Zung Anxiety Scale scores began at 61 (severe range) (Fig. B). At 2 weeks, scores declined to 45, a 26% reduction, and by week 4 fell further to 42, a 31% reduction overall. This trajectory reflects a steady improvement from severe toward moderate anxiety levels.
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The largest improvements occurred in the first 2 weeks of use, suggesting rapid early relief. Continued use through 4 weeks consolidated these gains, with patients showing both significant and sustained reductions in anxiety. This pattern supports the potential of non-invasive vagus nerve stimulation to deliver fast, meaningful, and lasting improvements in emotional well-being.

After the trial concluded, the devices were gifted to participants so they could continue using them. At the 6-month follow-up, 27 out of 37 participants or 73% reported still using the product at least three times per week. This sustained engagement indicates that many patients found continued value in ongoing use beyond the initial study period.

Daily use of non-invasive vagus nerve stimulation was associated with rapid and clinically significant reductions in anxiety severity, with participants improving from severe to mild anxiety within 2 weeks and maintaining benefits at 4 weeks. High retention at 6 months suggests strong user acceptability and continued perceived benefit.

Improvements were observed on both the GAD-7 and Zung scales, strengthening the validity of the findings. The GAD-7, focused on core clinical symptoms, showed a faster and larger reduction. The Zung scale, which also captures physical and emotional aspects of anxiety, showed steadier declines. Together, the convergence across these two distinct measures indicates that the intervention reduced both clinical severity and broader daily impacts of anxiety.

These findings support nVNS as a safe, accessible, and effective adjunctive intervention for anxiety disorders, warranting further controlled clinical trials.

Keywords

Vagus Nerve, Heart Rate Variability (HRV), GAD-7, ZUNG-20, Anxiety Relief