Several parameters should seriously be considered in, almost, every pathology before drawing the line of treatment. Patients are not alike even when they are twins. Individual variation is a reality that should be taken in consideration.
On top of this, comes the response to pain. The best example is the delivery of a baby; while one lady shouts loudly, another is very quiet. Some consider the pain stimulus as intense, because of psychogenic factors, while others show a calm response for the same condition.