Nervous System Dysregulation: What’s Happening in Your Body — And How Therapy Can Help

You’re exhausted but can’t sleep. You feel anxious with no clear trigger. Small things set you off more than they used to. You swing between emotional overwhelm and a strange flatness — like you’re watching your life from behind glass. If any of this sounds familiar, your nervous system may be dysregulated — and understanding why this happens is the first step toward genuine healing.

Nervous system dysregulation has become one of the most discussed concepts in modern trauma-informed therapy — and for good reason. It bridges neuroscience, psychology, and lived experience in ways that help people finally make sense of symptoms they’ve been carrying for years.

Understanding the Autonomic Nervous System

The autonomic nervous system (ANS) is the body’s automatic command centre — governing heart rate, breathing, digestion, immune function, and our responses to threat. It operates largely below conscious awareness, constantly scanning the environment for signals of safety or danger.

Most people learn a simple two-part model in school: sympathetic (fight-or-flight) and parasympathetic (rest-and-digest). But contemporary neuroscience offers a more nuanced picture — one that explains a much wider range of human experience.

Polyvagal Theory: The Science Behind Nervous System States

In the 1990s, neuroscientist Dr. Stephen Porges developed Polyvagal Theory — a framework that identifies three distinct states of the autonomic nervous system, each associated with a different quality of experience:

• Ventral Vagal (Safe and Social): When we feel safe, connected, and regulated. We can think clearly, connect authentically, and engage with the world. This is the optimal state for learning, creativity, and intimacy.
• Sympathetic (Mobilised): When we perceive threat, the system mobilises us for fight or flight. Heart rate increases, muscles tense, digestion slows. This state is adaptive in genuine danger — but when chronically activated, it produces anxiety, irritability, and hypervigilance.
• Dorsal Vagal (Collapsed/Shutdown): When threat feels inescapable or overwhelming, the oldest part of the nervous system can trigger a collapse response — numbness, dissociation, depression, disconnection, and a sense of helplessness.

Dysregulation occurs when the nervous system gets stuck — chronically activating survival states in situations that don’t require them. This is central to understanding trauma, anxiety, depression, and many physical health conditions. For a deeper understanding of Polyvagal Theory in clinical practice, Dr. Stephen Porges’ foundational 1994 work provides the original framework. The clinical resource Polyvagal Informed EMDR by Rebecca Kase (2023, W.W. Norton) is a guide for therapists integrating Polyvagal principles into EMDR practice

What Nervous System Dysregulation Looks Like

Dysregulation can present in many ways. Common experiences include:

• Chronic anxiety or a persistent sense of dread
• Emotional reactivity that feels disproportionate to the trigger
• Difficulty calming down after stress, even hours later
• Sleep disruption — difficulty falling asleep, staying asleep, or sleeping too much
• Digestive issues, chronic pain, or unexplained physical symptoms
• Emotional numbness, dissociation, or feeling “checked out”
• Difficulty being present — mind constantly racing or blank
• Feeling unsafe in situations that are objectively not dangerous

These are not signs of weakness. They are signs of a nervous system that learned to survive in difficult circumstances — and hasn’t yet learned that safety is available.

What Causes Nervous System Dysregulation?

Dysregulation typically develops in response to experiences that overwhelm the nervous system’s capacity to process and recover. Common causes include:

• Childhood adversity — neglect, abuse, inconsistent caregiving, or a chronically stressful home environment
• Trauma — including single-event trauma (accidents, assault) and complex/developmental trauma
• Chronic stress — workplace pressure, caregiving demands, financial strain, systemic stress
• Medical illness — particularly conditions affecting the nervous system or immune system
• Adverse perinatal experiences — including birth complications or early hospitalisation

What the Research Says: Vagal Nerve Stimulation and Trauma

One of the most exciting areas of emerging research involves direct stimulation of the vagus nerve — the primary channel of the ventral vagal system — as a way to regulate the nervous system and address trauma symptoms.

A 2025 systematic review published in PMC (PMC12344430) examined the evidence for transcutaneous auricular vagal nerve stimulation (taVNS) in treating PTSD. The review found that the current evidence for VNS as a treatment for PTSD is limited and does not meet clinical expectations, with an overall very low certainty of evidence. However, the evidence does show that VNS may alter and reduce specific aspects associated with PTSD, including the reduction of anger responses and the attenuation of hyperarousal during psychological interventions. These effects appear to be short-lasting, and the impact of repeated administration on long-term autonomic function remains unknown(Read the review on PubMed Central)

Therefore, while device-based vagal nerve stimulation is still an emerging area of research and not yet a clinically proven standalone treatment for PTSD, these findings validate what body-based therapies have long understood: the nervous system can be accessed through the body, not only through the mind.

Therapeutic Approaches That Address Nervous System Dysregulation

Effective treatment for nervous system dysregulation goes beyond traditional talk therapy. The most effective approaches work with the body as well as the mind:

• Somatic Therapy: Body-centred approaches (including Somatic Experiencing, developed by Dr. Peter Levine) that track and release trauma held in the body
• EMDR (Eye Movement Desensitisation and Reprocessing): An evidence-based trauma therapy now increasingly integrated with Polyvagal principles, as outlined in Polyvagal Informed EMDR (Kase, 2023)
• Mindfulness-Based Interventions: MBSR and mindfulness-based CBT support the capacity to observe nervous system states without being overwhelmed by them
• Internal Family Systems (IFS): Addresses protective parts of the psyche that developed in response to overwhelming experience
• Polyvagal-informed therapy: Working explicitly with nervous system states to build greater flexibility and access to the ventral vagal “safe and social” state

The Centre for Addiction and Mental Health (CAMH) and the International Society for Traumatic Stress Studies (ISTSS) both recognize that trauma-informed care is essential, though specific guidelines often highlight evidence-based psychotherapies as primary treatments. Body-based approaches are increasingly recognized as valuable components of a comprehensive treatment plan.

Small Steps That Support Nervous System Regulation

While professional therapy is the most reliable path to deeper nervous system healing, certain practices can support regulation between sessions:

• Physiological sighs: A double inhale through the nose followed by a long exhale activates the parasympathetic system rapidly — one of the fastest ways to shift state
• Cold water on the face or wrists: Activates the dive reflex, slowing heart rate
• Rhythmic movement: Walking, rocking, or swaying activates the vestibular system and supports ventral vagal tone
• Safe social connection: Even brief, genuine moments of connection with safe others activate the ventral vagal system
• Humming or singing: Vibrates the vagus nerve directly through the vocal cords

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This article references: Porges, S.W. (1994), Polyvagal Theory; Kase, R. (2023), Polyvagal Informed EMDR, W.W. Norton; PMC systematic review on taVNS for PTSD (PMC12344430, 2025). External links are provided for informational purposes. Please consult a qualified mental health professional for personalised support.