If Approximately One in Every Five People in North America

If approximately one in every five people in North America suffers with a diagnosable mental illness at any given time,Violet wonders why more people in ages past did not have problems with mental illness.She researches the question and learns that the stressors of modern life are triggering more individuals' vulnerabilities to particular disorders.Though previous generations had many of the same vulnerability factors,the stressors were not great enough to create as much mental illness as researchers see today.This is referred to as the

A) incubus model.
B) vulnerability-stress model.
C) trephination model.
D) neue-abnormality model.