DSM-IV diagnostic criteria for PTSD are used by VA’s compensation and pension program, as required by the Code of Federal Regulations (38 CFR 4.130). DSM-IV is also accepted and relied on by private health-insurance companies, Medicare, Medicaid, and the Social Security Administration.

2. What would an evidence-based criteria set for diagnosis of PTSD include?

The diagnostic criteria for PTSD in DSM-IV (Box 2.1) are evidence-based and are the criteria most widely used by US health professionals. The criteria were developed by an expert task force assembled by APA in accordance with the process described in the introductory section of DSM-IV. The expert task force reviewed the evidence from the published scientific literature, reanalyzed data where necessary, and evaluated evidence from studies examining how the diagnostic criteria operate in real-world settings. A record of the evidence used by each task force is compiled in the several volumes of the DSM-IV Sourcebook (APA 2000).

3. What constitutes a stressor?

A stressor is any agent, condition, event, or other stimulus that results in a stress response. A stress response consists of behavioral and physiologic reactions that can cause changes in the functioning of an organism. A traumatic stressor, according to DSM-IV, involves two criteria: (1) the person experiences, witnesses, or is confronted with an event(s) that involves actual or threatened death or serious injury or threat to the physical integrity of oneself or others; and (2) the person’s response involves intense fear, helplessness, or horror. Traumatic events during wartime, for example, might include serving in dangerous military roles, such as driving a truck at risk for encountering roadside bombs, patrolling the streets, and searching homes for enemy combatants, suicide attacks, sexual assaults or severe sexual harassment, physical assault, duties involving graves registration, accidents causing serious injuries or death, friendly fire, serving in medical units, killing or