Post traumatic stress disorder (PTSD) is a psychiatric disorder that occurs after a severe stressor, such as an event that can lead to death, serious injury, or sexual assault. In PTSD, even though the traumatic event has ended, the exposed individual seems to feel the stress symptoms.

Symptoms experienced by PTSD include re-experiences or flashbacks of the traumatic event, avoidance, emotional accumulation, and exaggeration. Patients may experience nightmares, dissociation, and intense negative feelings such as guilt or thoughts. PTSD can cause disturbances and concentration, irritability, reactivity, excessive anxiety, impaired social or occupational functioning, to suicidal thoughts or behavior.

The recommended psychotherapy for PTSD is trauma-focused psychodynamic psychotherapy. This can include eye movement desensitization and reprocessing (EMDR), cognitive processing therapy, and CBT (cognitive-behavioral therapy). The first-line pharmacotherapy for this disorder is selective serotonin reuptake inhibitor (SSRI) drugs, such as sertraline.