This medical discipline is based on the premises that the body and mind are intrinsically and intimately connected, through different axes: microbiota-gut-brain axis, microbiota-gut-lung axis, microbiota-gut-skin axis, etc. and on the fact that cognitive, behavioral and emotional reactions can have an effect on biological/physiological processes and vice versa.

Through studies and assessments, PNIe focus on emotions, beliefs, thoughts, behavior, etc. that can affect the correct function of the immune, hormonal and neurological systems, as well as on their effect on the patient predisposition to present dysfunctions, symptoms, or diseases; it also focus on the influence that these factors have on recovery from disease and health recovery.

For short, PNIe studies the complex and intimate interactions between body, mind and immune system, and how these interactions affect overall health and wellbeing.

It is an approach or discipline to understand how emotional and psychological aspects affect biological function and how to use this in-depth scientific knowledge in the treatment of various medical conditions to improve and/or restore overall health.