A system of neurotransmitters, according to PNI research, is activated by thoughts and emotions. They send out a web of signals via our involuntary nervous system, and these messages are carried along a network of chemical pathways throughout the nervous, immune and endocrine systems to receptors in targeted cells and organs. There they affect heart rate, blood pressure, breathing, muscle tension and gastrointestinal activity. All these influences combine to determine how effectively the body will defend itself against bacteria, viruses, even tumor formation and autoimmune disease. Other system components like interleukins and growth factors are less well known.
Researchers theorize that they are the biochemical equivalents of our states of mind.
Through them, thoughts, emotions and behavior come to correlate with different kinds of health situations. Since cell-seeking messengers do not circulate without referring to what's going on in their owner's mind, all this chemistry carries important implications for positive thinkers. The placebo effect illustrates how perceptions can change biological reality. Scientific medicine acknowledges that at least 30 percent of patients in experimental medical tests confound trials by benefiting from placebo drugs and other simulated procedures. In certain experiments, patients improved more when medical professionals appeared to believe in their treatment and care about them.