Diagnosis of posttraumatic stress disorder is subject to the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV-TR).
Criteria include exposure to a traumatic event, persistent re-experiencing of trauma, persistent avoidance and emotional numbing, duration of symptoms for more than a month, and significant impairment.
Clinicians use the Trauma Screening Questionnaire and the PTSD Symptom Scale as diagnostic tools to detect the symptoms of PTSD and to determine the need for formal diagnostic assessment.