Psychological reaction to a highly stressful event which includes symptoms of depression, anxiety, and recurring nightmares is known as .

Post-traumatic stress disorder (PTSD)

Explanation:

Post-traumatic stress disorder (PTSD) is a form of mental disorder that occurs when an individual is unable to recover from the distress caused by experiencing or witnessing traumatic events that are shocking and terrifying. If a person is unable to recover from such traumatic events that keeps causing intense emotional and physical reactions that disrupts the person’s daily life and activity for more than a month, such condition can be diagnosed as Post-traumatic stress disorder (PTSD). Symptoms such as depression, anxiety etc, would continue for months and even years. Psychotherapy and some medications can be used to treat this order by reducing the symptoms.

answerbps;