Post-traumatic stress disorder involves

A) immediate reaction to stressful war experiences.
B) stress reactions in anticipation of a traumatic event.
C) psychological disturbance due to the experience of a major traumatic event.
D) psychotic reactions to chronic stress, which emerge after one leaves the stressful environment.

Post-traumatic stress disorder (PTSD) is a psychological disorder that can develop after experiencing or witnessing a traumatic event. Symptoms of PTSD include flashbacks, nightmares, avoidance, and increased arousal. The traumatic event may be related to combat, sexual assault, terrorism, natural disasters, or other life-threatening experiences. Therefore, option C is the best answer as it correctly describes the psychological disturbance due to the experience of a major traumatic event. Option A is not accurate as the reaction to a traumatic event may not be immediate. Option B is incorrect as stress reactions due to anticipation of a traumatic event are better described as anxiety disorders, such as generalized anxiety disorder. Option D is inaccurate as PTSD is not a psychotic disorder, and symptoms typically occur during or shortly after exposure to the traumatic event, not after leaving the stressful environment.