Can vagus nerve stimulation enhance our capacity for self-compassion

Can vagus nerve stimulation enhance our capacity for self-compassion?

The vagus nerve, known for regulating functions such as heart rate and breathing, is also involved in the regulation of emotional states like empathy, compassion, and well-being. In recent years, transcutaneous vagus nerve stimulation (tVNS) has gained attention as a non-invasive, safe, and promising technique to complement psychological interventions.

In a study led by Sunjeev Kamboj, researchers investigated whether stimulating this nerve could amplify the effects of contemplative practices, such as mental imagery training focused on self-compassion. Over eight sessions, 120 healthy participants were divided into four groups, combining either active or sham stimulation with two types of mental training: one focused on self-compassion and another neutral. The researchers measured variables such as self-compassion, self-criticism, mindfulness, heart rate variability, and attentional bias toward compassionate faces.

The results showed that combining tVNS with self-compassion training led to rapid and significant increases in self-compassion and mindfulness, already noticeable in the first session. Self-compassion training alone showed cumulative effects over the sessions. Additionally, participants who received tVNS exhibited a further increase in trait self-compassion.

Interestingly, changes in pupil size and eye movements – indicators linked to attention and emotional response – suggest that the intervention subtly but measurably influenced how the brain responds to emotional stimuli. These findings open new perspectives for integrating neurostimulation and contemplative practices in the promotion of mental health and well-being.

This study was published in the scientific journal Psychological Medicine, in the article Electroceutical enhancement of self-compassion training using transcutaneous vagus nerve stimulation: results from a preregistered fully factorial randomized controlled trial, as a part of research project 140/20 - Stimulating compassion: Using transcutaneous vagus nerve stimulation (tVNS) to probe compassionate behaviour, supported by the Bial Foundation.



ABSTRACT


Background
Physiological signals conveyed by the vagus nerve may generate quiescent psychological states conducive to contemplative practices. This suggests that vagal neurostimulation could interact with contemplative psychotherapies (e.g. mindfulness and compassion-based interventions) to augment their efficacy.


Methods
In a fully factorial experimental trial, healthy adults (n = 120) were randomized to transcutaneous vagus nerve stimulation (tVNS) plus Self-Compassion-Mental-Imagery Training (SC-MIT) or alternative factorial combinations of stimulation (tVNS or sham) plus mental imagery training (MIT: SC-MIT or Control-MIT). Primary outcomes were self-reported state self-compassion, self-criticism, and heart rate variability (HRV). Exploratory outcomes included state mindfulness and oculomotor attentional bias to compassion-expressing faces. Most outcomes were assessed acutely on session 1 at the pre-stimulation (T1), peri-stimulation (T2), and post-MIT + stimulation (T3) timepoints, and after daily stimulation+MIT sessions (eight sessions).


Results
During session 1, a significant Timepoint × Stimulation × MIT interaction (p = 0.025) was observed, reflecting a larger acute T1→T3 increase in state self-compassion after tVNS+SC-MIT, with similar rapid effects on state mindfulness.

Additionally, significant Session × MIT and Session × Stimulation interactions (p ≤ 0.027) on state mindfulness (but not self-compassion) suggested that tVNS+SC-MIT’s effects may accumulate across sessions for some outcomes. By contrast, changes in state self-criticism and compassion-related attentional bias were only moderated by MIT (not stimulation) condition. HRV was unaffected by stimulation or MIT condition.


Conclusion
tVNS augmented the effects of SC-MIT and might, therefore, be a useful strategy for enhancing meditation-based psychotherapies. Our findings also highlight the value of oculomotor attentional metrics as responsive markers of self-compassion training and the continued need for sensitive indices of successful vagal stimulation.