Diathesis or terrain are the two terms used by Dr. Ménétrier. His definition is as follows: "A diathesis is located between health and disease; it reflects a state of imbalance that follows natural balance and precedes injury. It is a dysfunction that disrupts organic functioning and progressively leads to degeneration."
While we agree with the behavioral description of diatheses, we disagree on the term diathesis and its definition, because this presupposes a state of ideal equilibrium that does not exist in reality. And this is true even from birth, if only because heredity determines differences not only in personality but also in health.