The essential feature of PTSD claim is evidence that the Veteran has developed characteristic symptoms following exposure to an extreme traumatic stressor involving direct personal experience of an event that involves actual or threatened death or serious injury, or witnessing an event that involves death, injury, or a threat to the physical integrity of another person; or learning about unexpected or violent death, serious harm, or threat of death or injury experienced by a family member or other close associate.

“Service connection for PTSD requires medical evidence diagnosing the condition in accordance with sec. 4.125(a) of 38 C.F.R. Meaning it needs to reflect the diagnostic criteria in DSM-IV. A link established by medical evidence between current symptoms and an in service stressor; and credible supporting evidence that the claimed stressor occurred. Need evidence to show that the stressful event that resulted in PTSD actually happened during service. Any extreme traumatic event that satisfies the the diagnostic criteria in the DSM-IV may be accepted as a stressor.