Posttraumatic stress disorder is a trauma- and stress-related disorder linked to traumatic or terrifying event(s) that result in recurring affective, behavioral, and cognitive responses. Responses are triggered by events associated with the original trauma, with symptoms lasting at least a month, and in many cases years, following a specific trauma. Symptoms are highly variable and can manifest both psychologically and physically. Psychologic manifestations include obsessive negative thoughts, bad dreams, flashbacks, irritability, aggressiveness, fearfulness, dissociation, avoidance behaviors, sleep disturbances, lack of interest, hypervigilance, and poor concentration. Physical symptoms such as rapid breathing, increased heart rate, sweating, and tremors are often seen in posttraumatic stress disorder. The myriad symptoms seen with posttraumatic stress disorder have significant overlap with acute panic attacks as well as generalized anxiety disorder and/or major depressive disorder.

Many different types of trauma can cause posttraumatic stress disorder including violence, physical abuse, emotional abuse, sexual assault, witnessing a violent act, or experiencing severe pain, combat, torture, or acts of terrorism. In addition to emotional and physical trauma, particularly acute medical events such as cerebrovascular events, myocardial infarction, and prolonged intensive care unit hospitalizations have all been associated with posttraumatic stress disorder. The lifetime prevalence in the United States is approximately 6%-9%. Risk factors for posttraumatic stress disorder include low socioeconomic status, poor education, prior abuse, familial or other separations, traumatic childhood, and family history of psychiatric disease.

There is no well-understood pathway for the development of posttraumatic stress disorder. MRI studies have demonstrated decreased hippocampal, amygdala, and anterior cingulate cortex volume. Chronic adrenergic receptor down-regulation and decreased corticosteroid levels have also been associated with posttraumatic stress disorder.

Posttraumatic stress disorder can be a chronic condition with a lifelong duration. However, effective treatment does exist, and patients can make marked improvement in their quality of life and ability to function within society with intensive therapy.

Patients with this disorder may have an increased risk of various general medical conditions.