An Integrative Psychiatrist on the Connection Between the Vagus Nerve and Mental Health
By Dr. Lienna Wilson, Licensed Psychologist | Vagus Vitality
Many people think of psychiatry as the modality that just prescribes medication. But integrative psychiatry takes a more holistic view, looking closely at the mind-body connection and the ways the nervous system can be supported naturally, alongside medication when it is needed. Nervous system regulation, in this framing, is something closer to a foundation than a single calming technique.
To learn more about how that foundation is used in daily clinical work, I reached out to Dr. Amy O'Donnell, an integrative psychiatrist whose practice focuses on anxiety, depression, burnout, and trauma, women's mental health, and the often overlooked work of helping patients safely come off psychiatric medication.
As an integrative psychiatrist, how do you think about the connection between the body and mental health conditions?
As an integrative psychiatrist, Dr. O'Donnell keeps the mind-body connection at the center of how she thinks about conditions like anxiety and depression. “The vagus nerve is a really clear example of this,” she explains, “as it forms a bidirectional connection between your brain and other organs in your body, including your gut.” That kind of ongoing, two-way communication between the gut and the brain, carried out through neural, hormonal, and immune pathways, is well documented in the broader research literature (In et al., 2026). Dr. O'Donnell is careful to note that the full picture of how the vagus nerve carries out this communication is still being researched. What is well established is that the relationship is complex, involving the nervous system, the endocrine system, the immune system, and the gut microbiome all at once, rather than any single pathway acting alone.
How do you explain nervous system regulation to a patient for the first time?
When Dr. O'Donnell introduces the nervous system to a patient, she often compares it to the body's built-in security system, constantly scanning the environment to judge whether it is safe. When it senses danger, whether that is a real physical threat, chronic stress, poor sleep, illness, or emotional trauma, it shifts into a protective fight, flight, or freeze mode. “The vagus nerve is like a main brake pedal for your stress response,” she says. Nervous system regulation, in her framing, is simply the process of using specific habits and actions to activate the vagus nerve so the body can shift out of a fight or flight state and into a calmer rest and digest state.
What daily practices do you most often recommend to support vagal tone?
Two techniques come up most often in Dr. O'Donnell's work with patients: the dive reflex and diaphragmatic breathing.
The mammalian dive reflex is a built-in survival response that humans share with other mammals. When cold water touches the face, particularly around the eyes, cheeks, and forehead, the vagus nerve slows the heart rate in response. “This can be a helpful tool in the middle of a panic or anxiety attack,” Dr. O'Donnell says, “where you feel your heart racing, and it's hard to ground yourself and find calm in the moment.” Research on the diving response backs up its usefulness here: it has been shown to help reduce panic symptoms specifically (Kyriakoulis et al., 2021).
Diaphragmatic breathing, sometimes called belly breathing, is the other technique she frequently suggests. When anxiety sets in, breathing tends to become quick and shallow from the chest, which itself signals danger to the brain. Slowing the breath and breathing deeply into the diaphragm, felt as the belly expanding on the inhale, is thought to send the opposite message through the vagus nerve: that the body is safe. “Slowing and deepening the diaphragmatic breathing is thought to send calming signals via your vagus nerve,” Dr. O'Donnell notes. This lines up with what a recent systematic review and meta-analysis found: slow, voluntary breathing has a measurable effect on heart rate and heart rate variability, both markers tied to vagal activity (Laborde et al., 2022). There is also a proposed mechanism for why: slow, deep breathing may influence the pattern of signals sent from the lungs to the brain in a way that helps induce physiological relaxation (Noble & Hochman, 2019).
How do you think about the evidence behind supplements, botanicals, and nutritional approaches for the nervous system?
Dr. O'Donnell does use supplements, botanicals, and nutritional interventions as part of an integrative treatment plan, but she approaches them with the same scrutiny she brings to prescription medications: a careful review of the evidence, an individualized discussion of risks and benefits, and a clear understanding that “natural” does not automatically mean “safe” or “effective.”
She describes the evidence for these treatments as existing on a spectrum. Some, like lavender for anxiety, are backed by randomized controlled trials and a meta-analysis, which represents a higher level of evidence (Donelli et al., 2019). Others have only smaller clinical trials, observational data, or promising mechanistic research behind them, meaning the evidence is encouraging without being definitive.
The core message she returns to is that not every study carries the same weight in telling us whether its conclusions are likely to hold up. Factors like study type, sample size, and design all matter, and so does context: whether other research points in a different direction, or whether a topic simply has not been studied much at all. “This is a particular challenge in women's mental health research,” she notes, “especially in pregnancy,” where the evidence base is often thinner than it should be. For any treatment recommendation, supplements included, she weighs the risks, benefits, and evidence base together rather than leaning on any one of those alone.
You specialize in psychiatric de-prescribing and tapering. Do nervous system tools have a place when patients are coming off medication?
“I consider nervous system regulation to be a foundational piece of a successful psychiatric medication taper,” Dr. O'Donnell says. When someone has taken an antidepressant, benzodiazepine, or other psychiatric medication for months or years, the brain and nervous system adapt to its presence. As the dose is gradually reduced, the nervous system has to readjust, and it can become more sensitive or reactive during that window.
Withdrawal is one of the main risks of psychiatric de-prescribing, and nervous system tools have a real role in helping manage that reactivity and the withdrawal symptoms that can come with it, offering a non-medication way to calm a brain that is more activated and sensitive than usual.
She encourages patients to think of tapering as more than just lowering a dose. “It is an opportunity to strengthen the body's natural ability to regulate stress,” she says. Her goal throughout a taper is to set patients up for success both during the process, to manage withdrawal, and afterward, to help prevent relapse. Nervous system regulation is part of how she works toward both.
Taken together, Dr. O'Donnell's approach points to a hopeful message: many mental health symptoms respond well to mind-body techniques that work through the vagus nerve, from the dive reflex to diaphragmatic breathing and other daily habits that support vagal tone. Medications and supplements can be genuinely helpful along the way, but for many patients they are not necessarily a lifelong requirement. Under the careful supervision of a trained provider, they can often be tapered or discontinued, giving the body room to rebuild its own natural ability to regulate stress.
About Dr. Amy O'Donnell: Dr. Amy O'Donnell is an integrative psychiatrist who supports adults navigating anxiety, depression, burnout, trauma, psychiatric de-prescribing, medication tapering, and women's mental health. She combines medicine, psychotherapy, and natural approaches, and sees patients virtually in FL, NY, PA, and TX. To learn more, visit naturesflowpsych.com.
A note on medication and supplements mentioned here: Any change to a psychiatric medication, including tapering or discontinuation, should only be done under the guidance of a trained prescriber. Supplements and botanicals are not a substitute for medical care and can carry their own risks and interactions. Nothing in this piece is a recommendation to start or stop any treatment and should be discussed with your healthcare provider.
References
Donelli, D., Antonelli, M., Bellinazzi, C., Gensini, G. F., & Firenzuoli, F. (2019). Effects of lavender on anxiety: A systematic review and meta-analysis. Phytomedicine, 65, 153099. https://doi.org/10.1016/j.phymed.2019.153099
In, S. Y., Cho, T. H., & Yang, H. M. (2026). The vagus nerve as a neurovisceral interface: A comprehensive review. Frontiers in Neuroscience, 20, 1878765. https://doi.org/10.3389/fnins.2026.1878765
Kyriakoulis, P., Kyrios, M., Nardi, A. E., Freire, R. C., & Schier, M. (2021). The implications of the diving response in reducing panic symptoms. Frontiers in Psychiatry, 12, 784884. https://doi.org/10.3389/fpsyt.2021.784884
Laborde, S., Allen, M. S., Borges, U., Dosseville, F., Hosang, T. J., Iskra, M., Mosley, E., Salvotti, C., Spolverato, L., Zammit, N., & Javelle, F. (2022). Effects of voluntary slow breathing on heart rate and heart rate variability: A systematic review and a meta-analysis. Neuroscience & Biobehavioral Reviews, 138, 104711. https://doi.org/10.1016/j.neubiorev.2022.104711
Noble, D. J., & Hochman, S. (2019). Hypothesis: Pulmonary afferent activity patterns during slow, deep breathing contribute to the neural induction of physiological relaxation. Frontiers in Physiology, 10, 1176. https://doi.org/10.3389/fphys.2019.01176