In recent decades, a deeper understanding of the mind-body connection has emerged, revealing how the mind influences the body and vice versa. One of the most exciting fields exploring this relationship is psycho-neuroimmunology (PNI).

PNI studies how the mind, the nervous system, and the immune system interact to affect overall health. This growing field provides insights into how our mental health influences immune function, stress responses, and chronic illness.

As a therapist, I often see how stress, trauma, and unresolved emotions impact physical health. Fortunately, therapy, especially trauma-informed methods like Internal Family Systems, can help address these emotional stressors and provide support for overall mind-body healing.

In this article, I’ll go through some of the science behind PNI and how therapy can help balance the mind-body connection.

As a trained epidemiologist, I feel like I need to add a small disclaimer here before we get started: While I cite scientific studies that show some evidence for the role of mental health in physical illness, this field is relatively new and there is a lot more research that needs to be done in order for us to fully understand the connection and mechanisms between our minds and bodies.

What Is Psycho-Neuroimmunology?

Psycho-neuroimmunology (PNI) is an interdisciplinary field that examines how the brain, emotions, and immune system communicate. The idea that the mind and body are connected isn’t new, but PNI provides scientific insight into how mental and emotional factors influence physical health.

The nervous system plays a key role in translating mental and emotional experiences into physical responses. When we're emotionally stressed, the body activates the hypothalamic-pituitary-adrenal (HPA) axis, which regulates the body's stress response and the release of cortisol, a hormone that can suppress immune function if elevated for long periods.

The immune system defends the body against illness, but it also responds to psychological stress. Studies show that chronic stress weakens the immune system, making the body more susceptible to illness and inflammation. This is why continuous stress can lead to frequent illnesses or slower recovery.

The Role of Emotional Trauma in Physical Health

Chronic stress and unresolved emotional trauma can have far-reaching effects on our physical health. Dr. Gabor Maté, in his book When the Body Says No, explores how emotional repression and unresolved psychological pain are linked to a range of physical diseases.

Maté highlights cases of cancer, autoimmune disorders, and chronic fatigue syndrome, explaining that when emotions are suppressed, the body often takes on the burden, leading to various stress-related illnesses.

Gabor’s claims are backed by research that has shown a connection between Adverse Childhood Experiences (ACEs) and the likelihood of developing autoimmune disorders later in life. ACEs include traumatic experiences such as abuse, neglect, and household dysfunction during childhood.

The ACE study found that individuals with higher ACE scores were significantly more likely to develop autoimmune conditions like rheumatoid arthritis and lupus. Chronic stress from these early-life adversities may cause dysregulation of the immune system, increasing the risk of autoimmune disease development. This type of lasting impact of trauma on the body's stress response and immune system shows how early emotional stress can lead to long-term physical health issues.

The Interplay Between Chronic Stress and Neuroinflammation

Beyond these broader connections between mind and body, research into psycho-neuroimmunology provides a deeper look into the physiological mechanisms at play. Chronic stress, for example, can lead to neuroinflammation—a process where stress causes the immune system to release inflammatory markers that disrupt brain function and can contribute to conditions such as depression. Studies on neuroinflammation show that elevated levels of these markers have been linked to treatment-resistant depression as seen here and here.

Chronic stress can also lead to glucocorticoid resistance, where the body's ability to manage inflammation through cortisol is impaired. This resistance can exacerbate systemic inflammation, which increases vulnerability to physical health problems like cardiovascular disease and autoimmune disorders according to this study. Over time, this ongoing inflammation takes a toll on both mental and physical well-being.

The relationship between chronic stress and immune function has been examined in cases such as caregivers of patients with chronic conditions like Alzheimer’s disease. The study showed that caregivers were found to be more susceptible to illnesses due to chronic stress and took longer to recover, highlighting the detrimental effects of prolonged stress on immune function.

Recent research also explores the connection between chronic stress and the gut-brain axis. Chronic stress can disrupt the gut microbiome, which impacts immune function, increases inflammation, and worsens mental health conditions like anxiety and depression.

While emotional factors play a significant role in many health conditions, PNI does not suggest that all illnesses are rooted in emotional causes. Traditional medical models remain essential for diagnosing and treating physical illnesses. However, PNI helps us understand the systemic interaction between the mind, body, and immune system, allowing us to approach health more holistically. It encourages us to think more broadly about how emotional states can influence physical health, without claiming that emotional causes are the sole factor.

Emotional Resilience and Immune Health

The good news is that research suggests that emotional resilience can influence immune function. One study showed that participants who underwent an eight-week mindfulness training program experienced fewer side effects after receiving a flu vaccine and had higher antibody responses than the control group.

There is also a big meta-analysis that systematically reviewed the effects of mindfulness meditation on the immune system across various studies. The researchers found statistically significant reductions in pro-inflammatory cytokines such as IL-6, as well as increases in immune system markers like CD4+ T cells in some of the studies, which are crucial in defending against infections and promoting immune health.

While these results are promising, a lot of the research findings remain tentative. Many of the studies have small sample sizes and they use short-term interventions, so more robust research is needed to confirm the long-term benefits of mindfulness on immune function.

How IFS Therapy Can Help with Physical Illness

Therapy offers a structured way to address emotional stress and trauma, helping restore balance between mind and body. Internal Family Systems (IFS) therapy is one modality that can be used for healing the emotional aspects of chronic stress and trauma, which in turn can have a positive impact on the body.

Some evidence for the benefits of IFS on physical health were shown in a randomised controlled trial that examined the impact of IFS on rheumatoid arthritis. Over nine months, patients with RA who received IFS therapy showed statistically significant improvements in overall pain and physical function compared to a control group. Improvements in self-assessed joint pain, self-compassion, and depressive symptoms were maintained one year after the intervention ended, suggesting IFS can be a helpful complement to medical treatment.

IFS helps clients identify and work with parts that may carry unresolved pain or trauma, as well as parts that may push our nervous systems to shut-down or fight-or-flight order to try and protect us. By addressing these internal conflicts, IFS reduces the emotional burden on the body, promoting deeper healing.

Here’s how IFS can help:

Reducing Chronic Stress: By working with parts holding onto past trauma or emotional pain, IFS helps release chronic stress, which supports healthier immune function.
Promoting Emotional Balance: IFS fosters self-compassion and harmonious relationships between different parts of yourself, reducing emotional stress and physical symptoms.
Addressing Emotional Trauma: Trauma can manifest as physical pain or illness. IFS provides a safe, supportive space to process trauma and reduce its physical effects.

Incorporating somatic therapies or practices like yoga nidra alongside IFS can further deepen the mind-body connection and support healing.

Taking a Holistic Approach to Health

Psycho-neuroimmunology offers a new way of viewing health—one that integrates the mind, emotions, and body. While traditional medical treatments remain essential for diagnosing and treating physical illnesses, PNI encourages us to think more systemically about how mental and emotional states influence physical health.

If you’ve been struggling with chronic stress, autoimmune conditions, or feel that your emotional and physical health are connected, therapy may support you on your path to healing. By addressing emotional stressors and trauma, you can improve both mental and physical health, creating more balance and resilience in your life.

While I use IFS therapy, any trauma-informed therapy can be beneficial for mind-body issues. Other approaches you can explore include somatic experiencing, which releases trauma stored in the body, and therapists who apply polyvagal theory to regulate the nervous system. These methods, like IFS, address the emotional stress and trauma that affects physical health.

If you’d like to learn how therapy can support your mind-body healing, feel free to reach out. We can work together to understand the connections between your mind and body, helping you move toward better emotional and physical health.

Understanding Psycho-Neuroimmunology: The Interplay Between Stress, Emotions, and Physical Health