The PNEI system
Pyscho-neuro-endocrine-immunology (PNEI) is the study of how psychological and neurological factors on one hand and, endocrine and immune responses, on the other hand, influence each other interdependently.
The comprehension of the constant contact, communication and interdependence of these four systems, is the key for the identification of physiopatological mechanisms which lie at the heart of many if not all illnesses.
Factors like psychological-behavioural patterns, and, above all, sustained stress can change and alter the hormonal and immunological answer.
Psychological factors are the most common trigger of PNEI imbalance. Stressful states with sustain high cortisol and adrenalin levels disturb the hypothalamic-pituitary-adrenal (HPA) axis, resulting in thyroid problems and impaired immune responses.
In the PNEI vision, the neuroendocrine and immunitary systems act, respectively, as sense organs in the management of cognitive and non-cognitive stressors.
Exposure to repeated cognitive, non-cognitive, physical or environmental psycho-emotional stress of sufficient intensity can cause or exacerbate an imbalance (up or down –regulation) in the formation and metabolism of cerebral chemicals like dopamine, serotonin, and noradrenaline which are involved in mood regulation, attention, appetite control, reward, addiction and chronic inflammation .

Author's Bio: 

Max Corradi is a Complementary and Alternative Medicine (CAM) practitioner living and working in London, UK and a member of the British Register of Complementary Practitioners (BRCP). He has graduated with Honours in homeopathy and homotoxicology (complex homeopathy) at the Biomedic Centre in London. He has also received a Certificate in applied homotoxicology from the 'International Academy of homotoxicology', Baden-Baden-Germany and has obtained a Specialist Diploma in Physiological Regulating Medicine (PRM) at the International Academy of Physiological Regulating Medicine.