Psychoneuroimmunology: How Stress, Brain Function and Immunity Interact
Psychoneuroimmunology (PNI) is an interdisciplinary field that studies the interactions between the nervous system, the endocrine system, and the immune system. It examines how psychological states such as stress, helplessness, or emotional regulation can influence hormone secretion, neurotransmitter activity, inflammatory processes, and immune responses.
Cellular Behaviour Under Stress
Under conditions of chronic or uncontrollable stress, research shows that:
Cells increase the release of stress hormones such as cortisol and adrenaline.
Pro-inflammatory cytokines (e.g., IL-6, TNF-α) may be elevated, contributing to systemic inflammation.
Neurotransmitter systems, including dopamine, serotonin and noradrenaline, can become dysregulated, influencing mood, motivation, and behaviour.
These changes are often associated with alterations in brain activity (measured through EEG and neuroimaging techniques) and are correlated with behavioural patterns assessed through standardised psychological questionnaires in both clinical and non-clinical populations.
Methods Used in PNI Research
PNI integrates tools and concepts from:
Neuroscience – EEG, fMRI, and other neurophysiological measures to study brain function under stress and during regulation.
Endocrinology and Immunology – assays of cortisol, catecholamines, and cytokines to understand hormonal and immune responses.
Clinical and Health Psychology – validated scales and behaviour questionnaires to assess perceived stress, coping styles, affect, and mental health outcomes.
This combined approach allows researchers to map how subjective experience translates into objective biological change.
From Pharmacological to Behavioural Interventions
Historically, neuroscience and related clinical fields focused primarily on pharmacological treatment of stress-related and mood disorders. While medication remains important, growing evidence indicates that behavioural and cognitive interventions can significantly influence neuroendocrine and immune markers.
Research in PNI now examines how:
Cognitive-behavioural therapy (CBT)
Mindfulness-based interventions
Structured positive affirmations and guided visualisation
Belief and attitude modification (cognitive restructuring)
can reduce perceived stress, modulate cortisol levels, alter inflammatory profiles, and improve overall health and well-being.
Relevance for Clinical Practice and Research
Understanding psychoneuroimmunological mechanisms is essential for:
Designing integrative treatment protocols that combine psychological therapies with medical care.
Explaining why chronic psychological stress is a risk factor for a range of conditions, including mood disorders, cardiovascular disease, and immune-related illnesses.
Developing evidence-based programmes that target behaviour change to support both mental and physical health.
PNI therefore provides a scientific framework linking:
psychological processes → neural and endocrine responses → immune function → health outcomes.