A disorder resulting from exposure to a major stressor, with symptoms of anxiety, nightmares, poor sleep, reliving the event, and concentration problems, lasting for more than one month, is called _________.

A) acute stress disorder
B) external locus of control
C) catastrophic stress
D) post-traumatic stress disorder (PTSD)

The symptoms described in the question are all characteristic of PTSD, which is a disorder that can result from exposure to a traumatic event such as combat, sexual assault, or a natural disaster. Acute stress disorder is a similar condition, but the symptoms only last for a short period of time (up to one month). "External locus of control" and "catastrophic stress" are not terms used to describe specific mental health disorders.