Dr. Stanley Goldstein - Author and Psychologist

The human organism was once an undifferentiated mass from which subsystems developed: the enzymatic (hormone) system; the nervous system; the psychological system; and the organ system. Their boundaries are imprecise with activity in one being continuously communicated to others. A change in one that is caused by stress causes changes in others with their normal smooth integration being affected. Stress initially arouses helpful body defenses but too great stress causes a breakdown between system boundaries, a de-differentiation in which energy is discharged through violent fighting activity or running movements.
Mild anxiety is experienced as a signal of danger and can result in more efficient action or thought. But if the anxiety is too intense, with psychological means or behavior being unable to reduce it, primitive psychosomatic defenses attempt to replace the unsuccessful psychological maneuvers, stirring up harmful organ or system effects that can persist after the anxiety disappears.